├── .gitignore
├── LICENSE
├── README.md
├── chapter-1-introduction
├── 1.hello.c
├── 10.file-copying-2nd.c
├── 11.file-copying-3rd.c
├── 12.print-eof.c
├── 13.character-counting.c
├── 14.character-counting-for-double.c
├── 15.line-counting.c
├── 16.space-tab-line-counting.c
├── 17.repalce-multi-space.c
├── 18.replace-tab-backspace-backslash.c
├── 19.word-counting.c
├── 2.hello.c
├── 20.print-words.c
├── 21.array.c
├── 22.words-length-histogram-horizontal.c
├── 23.words-length-histogram-vertical.c
├── 24.characters-frequencies-histogram.c
├── 25.function-power.c
├── 26.fahrenheit-celsius-table-function.c
├── 27.max-line.c
├── 28.print-input-line-and-text.c
├── 29.print-length-80-line.c
├── 3.fahrenheit-celsius-table.c
├── 30.remove-line-end-space-and-tab.c
├── 31.reverses.c
├── 32.external-variables-and-scope.c
├── 33.detab.c
├── 34.entab.c
├── 35.fold-line.c
├── 36.remove-comments.c
├── 4.fahrenheit-celsius-table-float.c
├── 5.celsius-fahrenheit-table.c
├── 6.fahrenheit-celsius-table-for.c
├── 7.fahrenheit-celsius-table-reverse.c
├── 8.symbolic-constants.c
└── 9.file-copying-1st.c
├── chapter-2-types-operators-expressions
├── 1.ranges-of-variables.c
├── 10.getbits.c
├── 11.setbits.c
├── 12.invert.c
├── 13.rightrot.c
├── 14.bitcount.c
├── 15.bitcount2.c
├── 16.lower2.c
├── 2.loop-without-logical-operators.c
├── 3.atoi.c
├── 4.lower.c
├── 5.htio.c
├── 6.squeeze.c
├── 7.strcat.c
├── 8.squeeze2.c
└── 9.any.c
├── chapter-3-control-flow
├── 01.binsearch.c
├── 02.switch.c
├── 03.escape.c
├── 04.unescape.c
├── 05.atoi.c
├── 06.shellsort.c
├── 07.reverse.c
├── 08.expand.c
├── 09.itoa.c
├── 10.itob.c
├── 11.itoa.c
└── 12.trim.c
├── chapter-4-functions-and-program-structure
├── 1.simple-grep.c
├── 10.reverse.recursive.c
├── 11.swap-macro.c
├── 12.conditional-inclusion.c
├── 2.strrindex.c
├── 3.atof-test.c
├── 4.reverse-polish-calculator.c
├── 5.getop-with-static.c
├── 6.register-variable.c
├── 7.printd.c
├── 8.qsort.c
├── 9.itoa-recursive.c
├── atof.c
├── calc.h
├── getch.c
├── getop.c
├── mygetline.c
├── stack.c
└── sysv.h
├── chapter-5-pointers-and-arrays
├── 1.pointer.c
├── 10.strcpy-pointer-v1.c
├── 11.strcpy-pointer-v2.c
├── 12.strcpy-pointer-v3.c
├── 13.strcmp-array-subscript.c
├── 14.strcmp-pointer.c
├── 15.strcat-pointer.c
├── 16.strend.c
├── 17.strncpy.c
├── 18.strncat.c
├── 19.strncmp.c
├── 2.swap.c
├── 20.getline-pointer.c
├── 21.atoi.c
├── 22.itoa.c
├── 23.pointer-arrays.c
├── 24.pointer-arrays-without-alloc.c
├── 25.year-month-day.c
├── 26.pointer-array-init.c
├── 27.year-month-day-pointer.c
├── 28.echo-v1.c
├── 29.echo-v2.c
├── 3.getint.c
├── 30.find.c
├── 31.find.c
├── 32.expr.c
├── 33.detab.c
├── 34.entab.c
├── 35.detab-arg.c
├── 36.entab-arg.c
├── 37.tail.c
├── 38.pointers-to-functions.c
├── 39.sort-with-r.c
├── 4.getfloat.c
├── 40.sort-with-f.c
├── 41.sort-with-d.c
├── 42.dcl.c
├── 43.dcl-error-handle.c
├── 44.undcl.c
├── 44.undcl.test
├── 5.strlen-pointer.c
├── 6.alloc.c
├── 7.alloc.test.c
├── 8.strlen-address-arithmetic.c
├── 9.strcpy-array-subscript.c
├── bigtext
├── case-convert.c
├── getch.c
├── mygetline.c
├── numcmp.c
└── readlines-writelines.c
├── chapter-6-structures
├── 1.structures-and-functions.c
├── 2.keywords-count.c
├── 3.getword.c
├── 4.keywords-count-pointer.c
├── 5.words-count-binary-tree.c
├── 6.variables-group.c
├── 7.words-appear-lines.c
├── 8.table-lookup.c
└── getch.c
├── chapter-7-input-and-output
├── cat-v1.c
├── cat-v2.c
├── minprintf.c
└── scanf-sample.c
└── chapter-8-the-unix-system-interface
├── cp.c
├── dirent.h
├── fopen.c
├── fsize.c
├── malloc.c
└── sys-copy.c
/.gitignore:
--------------------------------------------------------------------------------
1 | *.out
2 | *.txt
3 | *.swp
4 | test.c
5 |
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443 | not accept this License. Therefore, by modifying or propagating a
444 | covered work, you indicate your acceptance of this License to do so.
445 |
446 | 10. Automatic Licensing of Downstream Recipients.
447 |
448 | Each time you convey a covered work, the recipient automatically
449 | receives a license from the original licensors, to run, modify and
450 | propagate that work, subject to this License. You are not responsible
451 | for enforcing compliance by third parties with this License.
452 |
453 | An "entity transaction" is a transaction transferring control of an
454 | organization, or substantially all assets of one, or subdividing an
455 | organization, or merging organizations. If propagation of a covered
456 | work results from an entity transaction, each party to that
457 | transaction who receives a copy of the work also receives whatever
458 | licenses to the work the party's predecessor in interest had or could
459 | give under the previous paragraph, plus a right to possession of the
460 | Corresponding Source of the work from the predecessor in interest, if
461 | the predecessor has it or can get it with reasonable efforts.
462 |
463 | You may not impose any further restrictions on the exercise of the
464 | rights granted or affirmed under this License. For example, you may
465 | not impose a license fee, royalty, or other charge for exercise of
466 | rights granted under this License, and you may not initiate litigation
467 | (including a cross-claim or counterclaim in a lawsuit) alleging that
468 | any patent claim is infringed by making, using, selling, offering for
469 | sale, or importing the Program or any portion of it.
470 |
471 | 11. Patents.
472 |
473 | A "contributor" is a copyright holder who authorizes use under this
474 | License of the Program or a work on which the Program is based. The
475 | work thus licensed is called the contributor's "contributor version".
476 |
477 | A contributor's "essential patent claims" are all patent claims
478 | owned or controlled by the contributor, whether already acquired or
479 | hereafter acquired, that would be infringed by some manner, permitted
480 | by this License, of making, using, or selling its contributor version,
481 | but do not include claims that would be infringed only as a
482 | consequence of further modification of the contributor version. For
483 | purposes of this definition, "control" includes the right to grant
484 | patent sublicenses in a manner consistent with the requirements of
485 | this License.
486 |
487 | Each contributor grants you a non-exclusive, worldwide, royalty-free
488 | patent license under the contributor's essential patent claims, to
489 | make, use, sell, offer for sale, import and otherwise run, modify and
490 | propagate the contents of its contributor version.
491 |
492 | In the following three paragraphs, a "patent license" is any express
493 | agreement or commitment, however denominated, not to enforce a patent
494 | (such as an express permission to practice a patent or covenant not to
495 | sue for patent infringement). To "grant" such a patent license to a
496 | party means to make such an agreement or commitment not to enforce a
497 | patent against the party.
498 |
499 | If you convey a covered work, knowingly relying on a patent license,
500 | and the Corresponding Source of the work is not available for anyone
501 | to copy, free of charge and under the terms of this License, through a
502 | publicly available network server or other readily accessible means,
503 | then you must either (1) cause the Corresponding Source to be so
504 | available, or (2) arrange to deprive yourself of the benefit of the
505 | patent license for this particular work, or (3) arrange, in a manner
506 | consistent with the requirements of this License, to extend the patent
507 | license to downstream recipients. "Knowingly relying" means you have
508 | actual knowledge that, but for the patent license, your conveying the
509 | covered work in a country, or your recipient's use of the covered work
510 | in a country, would infringe one or more identifiable patents in that
511 | country that you have reason to believe are valid.
512 |
513 | If, pursuant to or in connection with a single transaction or
514 | arrangement, you convey, or propagate by procuring conveyance of, a
515 | covered work, and grant a patent license to some of the parties
516 | receiving the covered work authorizing them to use, propagate, modify
517 | or convey a specific copy of the covered work, then the patent license
518 | you grant is automatically extended to all recipients of the covered
519 | work and works based on it.
520 |
521 | A patent license is "discriminatory" if it does not include within
522 | the scope of its coverage, prohibits the exercise of, or is
523 | conditioned on the non-exercise of one or more of the rights that are
524 | specifically granted under this License. You may not convey a covered
525 | work if you are a party to an arrangement with a third party that is
526 | in the business of distributing software, under which you make payment
527 | to the third party based on the extent of your activity of conveying
528 | the work, and under which the third party grants, to any of the
529 | parties who would receive the covered work from you, a discriminatory
530 | patent license (a) in connection with copies of the covered work
531 | conveyed by you (or copies made from those copies), or (b) primarily
532 | for and in connection with specific products or compilations that
533 | contain the covered work, unless you entered into that arrangement,
534 | or that patent license was granted, prior to 28 March 2007.
535 |
536 | Nothing in this License shall be construed as excluding or limiting
537 | any implied license or other defenses to infringement that may
538 | otherwise be available to you under applicable patent law.
539 |
540 | 12. No Surrender of Others' Freedom.
541 |
542 | If conditions are imposed on you (whether by court order, agreement or
543 | otherwise) that contradict the conditions of this License, they do not
544 | excuse you from the conditions of this License. If you cannot convey a
545 | covered work so as to satisfy simultaneously your obligations under this
546 | License and any other pertinent obligations, then as a consequence you may
547 | not convey it at all. For example, if you agree to terms that obligate you
548 | to collect a royalty for further conveying from those to whom you convey
549 | the Program, the only way you could satisfy both those terms and this
550 | License would be to refrain entirely from conveying the Program.
551 |
552 | 13. Use with the GNU Affero General Public License.
553 |
554 | Notwithstanding any other provision of this License, you have
555 | permission to link or combine any covered work with a work licensed
556 | under version 3 of the GNU Affero General Public License into a single
557 | combined work, and to convey the resulting work. The terms of this
558 | License will continue to apply to the part which is the covered work,
559 | but the special requirements of the GNU Affero General Public License,
560 | section 13, concerning interaction through a network will apply to the
561 | combination as such.
562 |
563 | 14. Revised Versions of this License.
564 |
565 | The Free Software Foundation may publish revised and/or new versions of
566 | the GNU General Public License from time to time. Such new versions will
567 | be similar in spirit to the present version, but may differ in detail to
568 | address new problems or concerns.
569 |
570 | Each version is given a distinguishing version number. If the
571 | Program specifies that a certain numbered version of the GNU General
572 | Public License "or any later version" applies to it, you have the
573 | option of following the terms and conditions either of that numbered
574 | version or of any later version published by the Free Software
575 | Foundation. If the Program does not specify a version number of the
576 | GNU General Public License, you may choose any version ever published
577 | by the Free Software Foundation.
578 |
579 | If the Program specifies that a proxy can decide which future
580 | versions of the GNU General Public License can be used, that proxy's
581 | public statement of acceptance of a version permanently authorizes you
582 | to choose that version for the Program.
583 |
584 | Later license versions may give you additional or different
585 | permissions. However, no additional obligations are imposed on any
586 | author or copyright holder as a result of your choosing to follow a
587 | later version.
588 |
589 | 15. Disclaimer of Warranty.
590 |
591 | THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
592 | APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
593 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
594 | OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
595 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
596 | PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
597 | IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
598 | ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
599 |
600 | 16. Limitation of Liability.
601 |
602 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
603 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
604 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
605 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
606 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
607 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
608 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
609 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
610 | SUCH DAMAGES.
611 |
612 | 17. Interpretation of Sections 15 and 16.
613 |
614 | If the disclaimer of warranty and limitation of liability provided
615 | above cannot be given local legal effect according to their terms,
616 | reviewing courts shall apply local law that most closely approximates
617 | an absolute waiver of all civil liability in connection with the
618 | Program, unless a warranty or assumption of liability accompanies a
619 | copy of the Program in return for a fee.
620 |
621 | END OF TERMS AND CONDITIONS
622 |
623 | How to Apply These Terms to Your New Programs
624 |
625 | If you develop a new program, and you want it to be of the greatest
626 | possible use to the public, the best way to achieve this is to make it
627 | free software which everyone can redistribute and change under these terms.
628 |
629 | To do so, attach the following notices to the program. It is safest
630 | to attach them to the start of each source file to most effectively
631 | state the exclusion of warranty; and each file should have at least
632 | the "copyright" line and a pointer to where the full notice is found.
633 |
634 | {one line to give the program's name and a brief idea of what it does.}
635 | Copyright (C) {year} {name of author}
636 |
637 | This program is free software: you can redistribute it and/or modify
638 | it under the terms of the GNU General Public License as published by
639 | the Free Software Foundation, either version 3 of the License, or
640 | (at your option) any later version.
641 |
642 | This program is distributed in the hope that it will be useful,
643 | but WITHOUT ANY WARRANTY; without even the implied warranty of
644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
645 | GNU General Public License for more details.
646 |
647 | You should have received a copy of the GNU General Public License
648 | along with this program. If not, see .
649 |
650 | Also add information on how to contact you by electronic and paper mail.
651 |
652 | If the program does terminal interaction, make it output a short
653 | notice like this when it starts in an interactive mode:
654 |
655 | {project} Copyright (C) {year} {fullname}
656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
657 | This is free software, and you are welcome to redistribute it
658 | under certain conditions; type `show c' for details.
659 |
660 | The hypothetical commands `show w' and `show c' should show the appropriate
661 | parts of the General Public License. Of course, your program's commands
662 | might be different; for a GUI interface, you would use an "about box".
663 |
664 | You should also get your employer (if you work as a programmer) or school,
665 | if any, to sign a "copyright disclaimer" for the program, if necessary.
666 | For more information on this, and how to apply and follow the GNU GPL, see
667 | .
668 |
669 | The GNU General Public License does not permit incorporating your program
670 | into proprietary programs. If your program is a subroutine library, you
671 | may consider it more useful to permit linking proprietary applications with
672 | the library. If this is what you want to do, use the GNU Lesser General
673 | Public License instead of this License. But first, please read
674 | .
675 |
--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
1 | # The-C-Programming-Language-2nd-Edition
2 | Source code and solutions of exercises to _The C Programming Language 2nd Edition by Brian W. Kernighan and Dennis M. Ritchie_
3 |
4 | ## Exercises:
5 |
6 | ### 1. Introduction
7 | 1. [1-1](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/1.hello.c)
8 | 1. [1-2](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/2.hello.c)
9 | 1. [1-3](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/5.celsius-fahrenheit-table.c)
10 | 1. [1-4](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/5.celsius-fahrenheit-table.c)
11 | 1. [1-5](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/7.fahrenheit-celsius-table-reverse.c)
12 | 1. [1-6](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/11.file-copying-3rd.c)
13 | 1. [1-7](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/12.print-eof.c)
14 | 1. [1-8](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/16.space-tab-line-counting.c)
15 | 1. [1-9](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/17.repalce-multi-space.c)
16 | 1. [1-10](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/18.replace-tab-backspace-backslash.c)
17 | 1. 1-11 skipped
18 | 1. [1-12](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/20.print-words.c)
19 | 1. 1-13
20 | * [horizontal](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/22.words-length-histogram-horizontal.c)
21 | * [vertical](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/23.words-length-histogram-vertical.c)
22 | 1. [1-14](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/24.characters-frequencies-histogram.c)
23 | 1. [1-15](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/26.fahrenheit-celsius-table-function.c)
24 | 1. [1-16](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/28.print-input-line-and-text.c)
25 | 1. [1-17](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/29.print-length-80-line.c)
26 | 1. [1-18](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/30.remove-line-end-space-and-tab.c)
27 | 1. [1-19](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/31.reverses.c)
28 | 1. [1-20](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/33.detab.c)
29 | 1. [1-21](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/34.entab.c)
30 | 1. [1-22](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/35.fold-line.c)
31 | 1. [1-23](https://github.com/Heatwave/The-C-Programming-Language-2nd-Edition/blob/master/chapter-1-introduction/36.remove-comments.c)
32 | 1. 1-24 skipped
33 |
34 | ### 2. Types operators expressions
35 | 1. [2-1](./chapter-2-types-operators-expressions/1.ranges-of-variables.c)
36 | 1. [2-2](./chapter-2-types-operators-expressions/2.loop-without-logical-operators.c)
37 | 1. [2-3](./chapter-2-types-operators-expressions/3.atoi.c)
38 | 1. [2-4](./chapter-2-types-operators-expressions/8.squeeze2.c)
39 | 1. [2-5](./chapter-2-types-operators-expressions/9.any.c)
40 | 1. [2-6](./chapter-2-types-operators-expressions/11.setbits.c)
41 | 1. [2-7](./chapter-2-types-operators-expressions/12.invert.c)
42 | 1. [2-8](./chapter-2-types-operators-expressions/13.rightrot.c)
43 | 1. [2-9](./chapter-2-types-operators-expressions/15.bitcount2.c)
44 | 1. [2-10](./chapter-2-types-operators-expressions/16.lower2.c)
45 |
46 | ### 3. Control flow
47 | 1. [3-1](./chapter-3-control-flow/01.binsearch.c)
48 | 1. 3-2
49 | * [escape](./chapter-3-control-flow/03.escape.c)
50 | * [unescape](./chapter-3-control-flow/04.unescape.c)
51 | 1. [3-3](./chapter-3-control-flow/08.expand.c)
52 | 1. [3-4](./chapter-3-control-flow/09.itoa.c)
53 | 1. [3-5](./chapter-3-control-flow/10.itob.c)
54 | 1. [3-6](./chapter-3-control-flow/11.itoa.c)
55 |
56 | ### 4. Functions and program structure
57 | 1. [4-1](./chapter-4-functions-and-program-structure/2.strrindex.c)
58 | 1. [4-2](./chapter-4-functions-and-program-structure/3.atof-test.c)
59 | 1. [4-3, 4-3, 4-5, 4-6](./chapter-4-functions-and-program-structure/4.reverse-polish-calculator.c)
60 | 1. [4-7](./chapter-4-functions-and-program-structure/getch.c)
61 | 1. [4-8](./chapter-4-functions-and-program-structure/getch.c)
62 | 1. 4-9 skipped
63 | 1. 4-10 skipped
64 | 1. [4-11](./chapter-4-functions-and-program-structure/5.getop-with-static.c)
65 | 1. [4-12](./chapter-4-functions-and-program-structure/9.itoa-recursive.c)
66 | 1. [4-13](./chapter-4-functions-and-program-structure/10.reverse.recursive.c)
67 | 1. [4-14](./chapter-4-functions-and-program-structure/11.swap-macro.c)
68 |
69 | ### 5. pointers and arrays
70 | 1. [5-1](./chapter-5-pointers-and-arrays/3.getint.c)
71 | 1. [5-2](./chapter-5-pointers-and-arrays/4.getfloat.c)
72 | 1. [5-3](./chapter-5-pointers-and-arrays/15.strcat-pointer.c)
73 | 1. [5-4](./chapter-5-pointers-and-arrays/16.strend.c)
74 | 1. 5-5
75 | * [strcpy](17.strncpy.c)
76 | * [strncat](18.strncat.c)
77 | * [strncmp](19.strncmp.c)
78 | 1. [5-6](./chapter-5-pointers-and-arrays/20.getline-pointer.c)
79 | 1. [5-7](./chapter-5-pointers-and-arrays/24.pointer-arrays-without-alloc.c)
80 | 1. [5-8](./chapter-5-pointers-and-arrays/27.year-month-day-pointer.c)
81 | 1. [5-9](./chapter-5-pointers-and-arrays/27.year-month-day-pointer.c)
82 | 1. [5-10](./chapter-5-pointers-and-arrays/32.expr.c)
83 | 1. 5-11
84 | * [detab](./chapter-5-pointers-and-arrays/33.detab.c)
85 | * [entab](./chapter-5-pointers-and-arrays/34.entab.c)
86 | 1. 5-12
87 | * [detab](./chapter-5-pointers-and-arrays/35.detab-arg.c)
88 | * [entab](./chapter-5-pointers-and-arrays/36.entab-arg.c)
89 | 1. [5-13](./chapter-5-pointers-and-arrays/37.tail.c)
90 | 1. [5-14](./chapter-5-pointers-and-arrays/39.sort-with-r.c)
91 | 1. [5-15](./chapter-5-pointers-and-arrays/40.sort-with-f.c)
92 | 1. [5-16](./chapter-5-pointers-and-arrays/41.sort-with-d.c)
93 | 1. 5-17 skipped
94 | 1. [5-18](./chapter-5-pointers-and-arrays/43.dcl-error-handle.c)
95 | 1. [5-19](./chapter-5-pointers-and-arrays/44.undcl.c)
96 | 1. 5-20 skipped
97 |
98 | ### 6. structures
99 | 1. [6-1](./chapter-6-structures/3.getword.c)
100 | 1. [6-2](./chapter-6-structures/6.variables-group.c)
101 | 1. [6-3](./chapter-6-structures/7.words-appear-lines.c)
102 | 1. 6-4 skipped
103 | 1. [6-5](./chapter-6-structures/8.table-lookup.c)
104 | 1. 6-6 skipped
105 |
--------------------------------------------------------------------------------
/chapter-1-introduction/1.hello.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | printf("hello, world \n");
6 |
7 | }
8 |
--------------------------------------------------------------------------------
/chapter-1-introduction/10.file-copying-2nd.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | /* copy input to output; 2nd version */
4 | main()
5 | {
6 | int c;
7 |
8 | while ((c = getchar()) != EOF)
9 | putchar(c);
10 | }
11 |
--------------------------------------------------------------------------------
/chapter-1-introduction/11.file-copying-3rd.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | int c;
6 |
7 | c = getchar() != EOF;
8 |
9 | printf("%d\n", c);
10 | putchar(c);
11 | }
12 |
--------------------------------------------------------------------------------
/chapter-1-introduction/12.print-eof.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | printf("%d\n", EOF);
6 | }
7 |
--------------------------------------------------------------------------------
/chapter-1-introduction/13.character-counting.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | /* count characters in input; 1st version */
4 | main()
5 | {
6 | long int nc;
7 |
8 | nc = 0;
9 | while (getchar() != EOF)
10 | ++nc;
11 | printf("%ld\n", nc);
12 | }
13 |
--------------------------------------------------------------------------------
/chapter-1-introduction/14.character-counting-for-double.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | /* count characters in input; 2nd version */
4 | main()
5 | {
6 | double nc;
7 |
8 | for (nc = 0; getchar() != EOF; ++nc)
9 | ;
10 | printf("%.0f\n", nc);
11 | }
12 |
--------------------------------------------------------------------------------
/chapter-1-introduction/15.line-counting.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | int c, nl;
6 |
7 | nl = 0;
8 | while ((c = getchar()) != EOF)
9 | if (c == '\n')
10 | ++nl;
11 | printf("%d\n", nl);
12 | }
13 |
--------------------------------------------------------------------------------
/chapter-1-introduction/16.space-tab-line-counting.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | int c;
6 | int space, tab, nl;
7 |
8 | space = tab = nl = 0;
9 |
10 | while((c = getchar()) != EOF) {
11 | if (c == ' ') {
12 | space++;
13 | } else if (c == '\t') {
14 | tab++;
15 | } else if (c == '\n') {
16 | nl++;
17 | }
18 | }
19 | printf("space: %d\ntab: %d\nnew line: %d\n", space, tab, nl);
20 | }
21 |
--------------------------------------------------------------------------------
/chapter-1-introduction/17.repalce-multi-space.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | int c, pre;
6 |
7 | while ((c = getchar()) != EOF) {
8 | if (c != ' ' || pre != ' ') {
9 | putchar(c);
10 | }
11 | pre = c;
12 | }
13 | }
14 |
--------------------------------------------------------------------------------
/chapter-1-introduction/18.replace-tab-backspace-backslash.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | int c;
6 |
7 | while ((c = getchar()) != EOF) {
8 | if (c == '\t') {
9 | putchar('\\');
10 | c = 't';
11 | }
12 |
13 | if (c == '\b') {
14 | putchar('\\');
15 | c = 'b';
16 | }
17 |
18 | if (c == '\\') {
19 | putchar('\\');
20 | c = '\\';
21 | }
22 |
23 | putchar(c);
24 | }
25 | }
26 |
--------------------------------------------------------------------------------
/chapter-1-introduction/19.word-counting.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define IN 1
4 | #define OUT 0
5 |
6 | main()
7 | {
8 | int c, nl, nw, nc, state;
9 |
10 | state = OUT;
11 | nl = nw = nc = 0;
12 | while ((c = getchar()) != EOF) {
13 | ++nc;
14 | if (c == '\n')
15 | ++nl;
16 | if (c == ' ' || c == '\n' || c == '\t')
17 | state = OUT;
18 | else if (state == OUT) {
19 | state = IN;
20 | ++nw;
21 | }
22 | }
23 |
24 | printf("%d %d %d\n", nl, nw, nc);
25 | }
26 |
--------------------------------------------------------------------------------
/chapter-1-introduction/2.hello.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int main() {
4 | printf("Hello, World\c");
5 | }
6 |
--------------------------------------------------------------------------------
/chapter-1-introduction/20.print-words.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define IN 1
4 | #define OUT 0
5 |
6 | main()
7 | {
8 | int c, state;
9 |
10 | state = OUT;
11 |
12 | while ((c = getchar()) != EOF) {
13 | if (c == ' ' || c == '\n' || c == '\t') {
14 | if (state == IN) {
15 | putchar('\n');
16 | }
17 | state = OUT;
18 | } else {
19 | state = IN;
20 | putchar(c);
21 | }
22 | }
23 | }
24 |
--------------------------------------------------------------------------------
/chapter-1-introduction/21.array.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | int c, i, nwhite, nother;
6 | int ndigit[10];
7 |
8 | nwhite = nother = 0;
9 | for (i = 0; i < 10; ++i)
10 | ndigit[i] = 0;
11 |
12 |
13 | while ((c = getchar()) != EOF)
14 | if (c >= '0' && c <= '9')
15 | ++ndigit[c-'0'];
16 | else if (c== ' ' || c == '\n' || c == '\t')
17 | ++nwhite;
18 | else
19 | ++nother;
20 |
21 | printf("digits = ");
22 | for (i = 0; i < 10; ++i)
23 | printf(" %d", ndigit[i]);
24 | printf(", white space = %d, other = %d\n",
25 | nwhite, nother);
26 | }
27 |
--------------------------------------------------------------------------------
/chapter-1-introduction/22.words-length-histogram-horizontal.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define IN 0
4 | #define OUT 1
5 |
6 | main()
7 | {
8 | int state;
9 | int length, max;
10 | int count[999];
11 | int i, c, j;
12 |
13 | length = 0;
14 | max = 0;
15 | state = OUT;
16 |
17 | for (i = 0; i < 999; ++i)
18 | count[i] = 0;
19 |
20 | while ((c = getchar()) != EOF) {
21 | if (c == ' ' || c == '\n' || c == '\t') {
22 | state = OUT;
23 |
24 | if (length > max)
25 | max = length;
26 |
27 | if (length != 0)
28 | count[length]++;
29 | length = 0;
30 | } else if (state == OUT) {
31 | state = IN;
32 | length++;
33 | } else {
34 | length++;
35 | }
36 | }
37 |
38 | for (i = 0; i < max + 1; ++i) {
39 | printf("%2d: ", i);
40 | for (j = 0; j < count[i]; ++j) {
41 | putchar('#');
42 | }
43 | printf("\n");
44 | }
45 | }
46 |
--------------------------------------------------------------------------------
/chapter-1-introduction/23.words-length-histogram-vertical.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define IN 0
4 | #define OUT 1
5 | #define WORD_MAX_LENGTH 999
6 |
7 | main()
8 | {
9 | int state;
10 | int length, maxLength, maxCount;
11 | int count[WORD_MAX_LENGTH];
12 | int i, c, j;
13 |
14 | length = 0;
15 | maxLength = 0;
16 | maxCount = 0;
17 | state = OUT;
18 |
19 | for (i = 0; i < WORD_MAX_LENGTH; ++i)
20 | count[i] = 0;
21 |
22 | while ((c = getchar()) != EOF) {
23 | if (c == ' ' || c == '\n' || c == '\t') {
24 | state = OUT;
25 |
26 | if (length > maxLength)
27 | maxLength = length;
28 |
29 | if (length != 0)
30 | count[length]++;
31 |
32 | if (count[length] > maxCount)
33 | maxCount = count[length];
34 |
35 | length = 0;
36 | } else if (state == OUT) {
37 | state = IN;
38 | length++;
39 | } else {
40 | length++;
41 | }
42 | }
43 |
44 | for (i = maxCount; i > 0; --i) {
45 | printf("%2d: ", i);
46 |
47 | for (j = 1; j < maxLength + 1; ++j) {
48 | printf(" ");
49 | if (count[j] >= i)
50 | putchar('#');
51 | else
52 | putchar(' ');
53 | }
54 | putchar('\n');
55 | }
56 |
57 | printf(" ");
58 | for (i = 1; i < maxLength + 1; ++i)
59 | printf("%3d", i);
60 |
61 | printf("\n");
62 | }
63 |
--------------------------------------------------------------------------------
/chapter-1-introduction/24.characters-frequencies-histogram.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | int histogram[26];
6 | int c, i, j;
7 |
8 | for (i = 0; i < 26; ++i)
9 | histogram[i] = 0;
10 |
11 | while ((c = getchar()) != EOF) {
12 | if (c >= 'a' && c <= 'z') {
13 | histogram[c - 'a']++;
14 | }
15 | }
16 |
17 | for (i = 0; i < 26; ++i) {
18 | printf("%c: ", 'a' + i);
19 | for (j = 0; j < histogram[i]; ++j) {
20 | putchar('#');
21 | }
22 | putchar('\n');
23 | }
24 | }
25 |
--------------------------------------------------------------------------------
/chapter-1-introduction/25.function-power.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int power(int m, int n);
4 |
5 | main()
6 | {
7 | int i;
8 |
9 | for (i = 0; i < 10; ++i)
10 | printf("%d %d %d\n", i, power(2, i), power(-3, i));
11 | return 0;
12 | }
13 |
14 | int power(int base, int n)
15 | {
16 | int i, p;
17 |
18 | p = 1;
19 | for (i = 1; i <= n; ++i)
20 | p = p * base;
21 | return p;
22 | }
23 |
--------------------------------------------------------------------------------
/chapter-1-introduction/26.fahrenheit-celsius-table-function.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | float fahrToCelsius(float fahr);
4 |
5 | main()
6 | {
7 | float fahr, celsius;
8 | int lower, upper, step;
9 |
10 | lower = 0; /* lower limit of temperature table */
11 | upper = 300; /* upper limit */
12 | step = 20; /* step size */
13 |
14 | fahr = lower;
15 |
16 | printf("Fahrenheit-Celsius table\n");
17 | while (fahr <= upper) {
18 | printf("%3.0f %6.1f\n", fahr, fahrToCelsius(fahr));
19 | fahr = fahr + step;
20 | }
21 | }
22 |
23 | float fahrToCelsius(float fahr)
24 | {
25 | return (5.0 / 9.0) * (fahr - 32.0);
26 | }
27 |
--------------------------------------------------------------------------------
/chapter-1-introduction/27.max-line.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAXLINE 1000
4 |
5 | int myGetline(char line[], int maxline);
6 | void copy(char to[], char from[]);
7 |
8 | main()
9 | {
10 | int len;
11 | int max;
12 | char line[MAXLINE];
13 | char longest[MAXLINE];
14 |
15 | max = 0;
16 | while ((len = myGetline(line, MAXLINE)) > 0)
17 | if (len > max) {
18 | max = len;
19 | copy(longest, line);
20 | }
21 |
22 | if (max > 0)
23 | printf("%s", longest);
24 |
25 | return 0;
26 | }
27 |
28 | int myGetline(char s[], int lim)
29 | {
30 | int c, i;
31 |
32 | for (i = 0; i < lim - 1 && (c = getchar()) != EOF && c != '\n'; ++i)
33 | s[i] = c;
34 | if (c == '\n') {
35 | s[i] = c;
36 | ++i;
37 | }
38 | s[i] = '\0';
39 | return i;
40 | }
41 |
42 | void copy(char to[], char from[])
43 | {
44 | int i;
45 |
46 | i = 0;
47 | while ((to[i] = from[i]) != '\0')
48 | ++i;
49 | }
50 |
--------------------------------------------------------------------------------
/chapter-1-introduction/28.print-input-line-and-text.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAXLINE 1000
4 |
5 | int myGetline(char line[], int maxline);
6 | char
7 |
8 | main()
9 | {
10 | int len;
11 | int max;
12 | char line[MAXLINE];
13 |
14 | max = 0;
15 | while ((len = myGetline(line, MAXLINE)) > 0)
16 | printf("%d: %s", len, line);
17 |
18 | return 0;
19 | }
20 |
21 | int myGetline(char s[], int lim)
22 | {
23 | int c, i;
24 |
25 | i = 0;
26 |
27 | while((c = getchar()) != EOF && c != '\n') {
28 | if (i < lim - 1)
29 | s[i++] = c;
30 | else
31 | i++;
32 | }
33 |
34 | if (c == '\n' && i < lim - 1) {
35 | s[i++] = c;
36 | }
37 | s[i] = '\0';
38 | return i;
39 | }
40 |
--------------------------------------------------------------------------------
/chapter-1-introduction/29.print-length-80-line.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAXLINE 1000
4 | #define PRINT_LENGTH 80
5 |
6 | int myGetline(char line[], int maxline);
7 | char
8 |
9 | main()
10 | {
11 | int len;
12 | int max;
13 | char line[MAXLINE];
14 | char longest[MAXLINE];
15 |
16 | max = 0;
17 | while ((len = myGetline(line, MAXLINE)) > 0)
18 | if (len > PRINT_LENGTH) {
19 | printf("%s", line);
20 | }
21 |
22 | return 0;
23 | }
24 |
25 | int myGetline(char s[], int lim)
26 | {
27 | int c, i;
28 |
29 | for (i = 0; i < lim - 1 && (c = getchar()) != EOF && c != '\n'; ++i)
30 | s[i] = c;
31 | if (c == '\n') {
32 | s[i] = c;
33 | ++i;
34 | }
35 | s[i] = '\0';
36 | return i;
37 | }
38 |
--------------------------------------------------------------------------------
/chapter-1-introduction/3.fahrenheit-celsius-table.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | /* print Fahrenheit-Celsius table
4 | for fahr = 0, 20, ..., 300 */
5 | main() {
6 | int fahr, celsius;
7 | int lower, upper, step;
8 |
9 | lower = 0; /* lower limit of temperature table */
10 | upper = 300; /* upper limit */
11 | step = 20; /* step size */
12 |
13 | fahr = lower;
14 | while (fahr <= upper) {
15 | celsius = 5 * (fahr-32) / 9;
16 | printf("%3d %6d\n", fahr, celsius);
17 | fahr = fahr + step;
18 | }
19 | }
20 |
21 |
--------------------------------------------------------------------------------
/chapter-1-introduction/30.remove-line-end-space-and-tab.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAXLINE 1000
4 |
5 | int myGetline(char line[], int maxline);
6 | char
7 |
8 | main()
9 | {
10 | int len;
11 | int max;
12 | char line[MAXLINE];
13 | char longest[MAXLINE];
14 | int i;
15 |
16 | max = 0;
17 | while ((len = myGetline(line, MAXLINE)) > 0) {
18 | for (i = len; i >= 0; --i) {
19 | if (line[i] == ' ' || line[i] == '\t')
20 | line[i] = '\0';
21 | else if (line[i] == '\n' || line[i] == '\0')
22 | continue;
23 | else
24 | break;
25 | }
26 |
27 | if (line[0] != '\0' && line[0] != '\n') {
28 | printf("%s", line);
29 | }
30 | }
31 |
32 | return 0;
33 | }
34 |
35 | int myGetline(char s[], int lim)
36 | {
37 | int c, i;
38 |
39 | for (i = 0; i < lim - 1 && (c = getchar()) != EOF && c != '\n'; ++i)
40 | s[i] = c;
41 | if (c == '\n') {
42 | s[i] = c;
43 | ++i;
44 | }
45 | s[i] = '\0';
46 | return i;
47 | }
48 |
--------------------------------------------------------------------------------
/chapter-1-introduction/31.reverses.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAXLINE 999
4 |
5 | void reverse(char s[]);
6 | int myGetline(char line[], int maxline);
7 |
8 | int main()
9 | {
10 | char line[MAXLINE];
11 |
12 | while(myGetline(line, MAXLINE) > 0) {
13 | reverse(line);
14 | printf("%s", line);
15 | }
16 |
17 | return 0;
18 | }
19 |
20 | void reverse(char s[])
21 | {
22 | int len, i, left;
23 | char temp;
24 | len = 0;
25 | while (s[len] != '\n')
26 | len++;
27 |
28 | int middle;
29 | if ((len % 2) == 0)
30 | middle = len / 2;
31 | else
32 | middle = len / 2 + 1;
33 |
34 | for (i = len - 1; i >= middle; --i) {
35 | left = len - 1 - i;
36 | temp = s[left];
37 | s[left] = s[i];
38 | s[i] = temp;
39 | }
40 | }
41 |
42 | int myGetline(char s[], int maxline)
43 | {
44 | int c, i;
45 |
46 | for (i = 0; i < maxline -1 && (c = getchar()) != EOF && c!= '\n'; ++i)
47 | s[i] = c;
48 | if (c == '\n') {
49 | s[i] = c;
50 | ++i;
51 | }
52 | s[i] = '\0';
53 | return i;
54 | }
55 |
--------------------------------------------------------------------------------
/chapter-1-introduction/32.external-variables-and-scope.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAXLINE 1000
4 |
5 | int max;
6 | char line[MAXLINE];
7 | char longest[MAXLINE];
8 |
9 | int myGetline(void);
10 | void copy(void);
11 |
12 | main()
13 | {
14 | int len;
15 | extern int max;
16 | extern char longest[];
17 |
18 | max = 0;
19 | while ((len = myGetline()) > 0)
20 | if (len > max) {
21 | max = len;
22 | copy();
23 | }
24 |
25 | if (max > 0)
26 | printf("%s", longest);
27 |
28 | return 0;
29 | }
30 |
31 | int myGetline(void)
32 | {
33 | int c, i;
34 | extern char line[];
35 |
36 | for (i = 0; i < MAXLINE - 1
37 | && (c = getchar()) != EOF && c != '\n'; ++i)
38 | line[i] = c;
39 |
40 | if (c == '\n') {
41 | line[i] = c;
42 | ++i;
43 | }
44 |
45 | line[i] = '\0';
46 | return i;
47 | }
48 |
49 | void copy(void)
50 | {
51 | int i;
52 | extern char line[], longest[];
53 |
54 | i = 0;
55 | while ((longest[i] = line[i]) != '\0')
56 | ++i;
57 | }
58 |
--------------------------------------------------------------------------------
/chapter-1-introduction/33.detab.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | int c, n, i;
6 | int cur;
7 |
8 | n = 8;
9 |
10 | cur = 0;
11 |
12 | while ((c = getchar()) != EOF) {
13 | if (c == '\t') {
14 | for (i = n - cur; i > 0; --i)
15 | putchar(' ');
16 |
17 | cur = 0;
18 | } else {
19 | putchar(c);
20 | cur++;
21 | if (cur > n)
22 | cur = 0;
23 | }
24 | }
25 | }
26 |
--------------------------------------------------------------------------------
/chapter-1-introduction/34.entab.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAXLINE 1000
4 |
5 | int myGetline(char line[], int maxline);
6 |
7 | main()
8 | {
9 | int c, len;
10 | int i;
11 | char line[MAXLINE];
12 | int tabstop;
13 |
14 | tabstop = 8;
15 | while ((len = myGetline(line, MAXLINE)) > 0) {
16 | int spaceCount = 0;
17 |
18 | for (i = 0; i < len; ++i) {
19 | if (line[i] == ' ')
20 | spaceCount++;
21 | else
22 | spaceCount = 0;
23 |
24 | if (spaceCount == tabstop) {
25 | }
26 | }
27 | printf("%s", line);
28 | }
29 | }
30 |
31 | int myGetline(char s[], int lim)
32 | {
33 | int c, i;
34 |
35 | for (i = 0; i < lim - 1 && (c = getchar()) != EOF && c != '\n'; ++i)
36 | s[i] = c;
37 | if (c == '\n') {
38 | s[i] = c;
39 | ++i;
40 | }
41 | s[i] = '\0';
42 | return i;
43 | }
44 |
--------------------------------------------------------------------------------
/chapter-1-introduction/35.fold-line.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAXLINE 1000
4 |
5 | int myGetline(char line[], int maxline);
6 |
7 | main()
8 | {
9 | int len;
10 | int lineLenLimit;
11 | char line[MAXLINE], outputLine[MAXLINE];
12 | int i, j;
13 | int foldCol;
14 |
15 |
16 | lineLenLimit = 10;
17 |
18 | while ((len = myGetline(line, MAXLINE)) > 0) {
19 | for (i = 0; i < len; ++i) {
20 | if (i != 0 && (i + 1) % lineLenLimit == 0) {
21 | for (j = i; j > 0; --j) {
22 | if (line[j] != ' ' && line[j] != '\t') {
23 | foldCol = j;
24 | break;
25 | }
26 | }
27 |
28 | for (j = 0; j < foldCol - i + lineLenLimit; ++j) {
29 | outputLine[j] = line[j + i - lineLenLimit + 1];
30 | }
31 | outputLine[j] = '\n';
32 | outputLine[j + 1] = '\0';
33 |
34 | printf("%s", outputLine);
35 | } else if (i == len - 1) {
36 | for (j = 0; j < i % lineLenLimit; ++j)
37 | outputLine[j] = line[j + i - (i % lineLenLimit)];
38 |
39 | outputLine[j] = '\0';
40 |
41 | printf("%s", outputLine);
42 | }
43 | }
44 | }
45 | }
46 |
47 | int myGetline(char s[], int lim)
48 | {
49 | int c, i;
50 |
51 | for (i = 0; i < lim - 1 && (c = getchar()) != EOF && c != '\n'; ++i)
52 | s[i] = c;
53 | if (c == '\n') {
54 | s[i] = c;
55 | ++i;
56 | }
57 | s[i] = '\0';
58 | return i;
59 | }
60 |
--------------------------------------------------------------------------------
/chapter-1-introduction/36.remove-comments.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define OUT_COMMENT 0
4 | #define IN_COMMENT 1
5 | #define IN_ONE_LINE_COMMENT 2
6 |
7 | #define OUT_STRING 0
8 | #define IN_STRING 1
9 |
10 | /*
11 | * This is the exercise 1-23 of The C Programming Language
12 | * remove all of the comments in the C program
13 | */
14 |
15 | main()
16 | {
17 | int c;
18 | int status, stringStatus;
19 | int preChar;
20 |
21 | printf("/*asdqwe*/");
22 |
23 | status = OUT_COMMENT;
24 | stringStatus = OUT_STRING;
25 |
26 | while((c = getchar()) != EOF) {
27 | /* This is the comment for test */
28 | if (status == OUT_COMMENT) {
29 | if (stringStatus == OUT_STRING) {
30 | if (c == '"') {
31 | stringStatus = IN_STRING;
32 | putchar(c);
33 | continue;
34 | }
35 |
36 | if (c == '/' && preChar == '/') {
37 | status = IN_ONE_LINE_COMMENT;
38 | preChar = '\n';
39 | continue;
40 | } else if (c == '/') {
41 | preChar = c;
42 | continue;
43 | }
44 |
45 | if (c == '*' && preChar == '/') {
46 | status = IN_COMMENT;
47 | } else if (preChar == '/') {
48 | putchar('/');
49 | putchar(c);
50 | } else {
51 | putchar(c);
52 | }
53 | } else {
54 | if (c == '"') {
55 | stringStatus = OUT_STRING;
56 | putchar(c);
57 | } else {
58 | putchar(c);
59 | }
60 | }
61 | } else if (status == IN_ONE_LINE_COMMENT) {
62 | if (c == '\n') {
63 | putchar('\n');
64 | status = OUT_COMMENT;
65 | }
66 | } else {
67 | if (c == '/' && preChar == '*') {
68 | status = OUT_COMMENT;
69 | preChar = 0;
70 | continue; // comment for test
71 | }
72 | }
73 | preChar = c;
74 | }
75 |
76 | printf("// test one line comment");
77 | }
78 |
--------------------------------------------------------------------------------
/chapter-1-introduction/4.fahrenheit-celsius-table-float.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | float fahr, celsius;
6 | int lower, upper, step;
7 |
8 | lower = 0; /* lower limit of temperature table */
9 | upper = 300; /* upper limit */
10 | step = 20; /* step size */
11 |
12 | fahr = lower;
13 |
14 | printf("Fahrenheit-Celsius table\n");
15 | while (fahr <= upper) {
16 | celsius = (5.0 / 9.0) * (fahr - 32.0);
17 | printf("%3.0f %6.1f\n", fahr, celsius);
18 | fahr = fahr + step;
19 | }
20 | }
21 |
--------------------------------------------------------------------------------
/chapter-1-introduction/5.celsius-fahrenheit-table.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | float fahr, celsius;
6 | int lower, upper, step;
7 |
8 | lower = 0; /* lower limit of temperature table */
9 | upper = 300; /* upper limit */
10 | step = 20; /* step size */
11 |
12 | celsius = lower;
13 |
14 | printf("Celsius-Fahrenheit table\n");
15 | while (celsius <= upper) {
16 | fahr = celsius / (5.0 / 9.0) + 32.0;
17 | printf("%3.0f %6.1f\n", celsius, fahr);
18 | fahr = fahr + step;
19 | celsius += step;
20 | }
21 | }
22 |
--------------------------------------------------------------------------------
/chapter-1-introduction/6.fahrenheit-celsius-table-for.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | int fahr;
6 |
7 | for (fahr = 0; fahr <= 300; fahr = fahr + 20)
8 | printf("%3d %6.1f\n", fahr, (5.0 / 9.0) * (fahr - 32));
9 | }
10 |
--------------------------------------------------------------------------------
/chapter-1-introduction/7.fahrenheit-celsius-table-reverse.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | int fahr;
6 |
7 | for (fahr = 300; fahr >= 0; fahr = fahr - 20)
8 | printf("%3d %6.1f\n", fahr, (5.0 / 9.0) * (fahr - 32));
9 | }
10 |
--------------------------------------------------------------------------------
/chapter-1-introduction/8.symbolic-constants.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define LOWER 0
4 | #define UPPER 300
5 | #define STEP 20
6 |
7 | main()
8 | {
9 | int fahr;
10 |
11 | for (fahr = LOWER; fahr <= UPPER; fahr = fahr + STEP)
12 | printf("%3d %6.1f\n", fahr, (5.0 / 9.0) * (fahr - 32));
13 | }
14 |
--------------------------------------------------------------------------------
/chapter-1-introduction/9.file-copying-1st.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | /* copy input to output; 1st version */
4 | main()
5 | {
6 | int c;
7 |
8 | c = getchar();
9 | while (c != EOF)
10 | {
11 | putchar(c);
12 | c = getchar();
13 | }
14 | }
15 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/1.ranges-of-variables.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | main()
5 | {
6 | printf("From limits.h:\n");
7 | printf("CHAR_BIT: %d\n", CHAR_BIT);
8 | printf("CHAR_MAX: %d\n", CHAR_MAX);
9 | printf("CHAR_MIN: %d\n", CHAR_MIN);
10 | printf("INT_MAX: %d\n", INT_MAX);
11 | printf("INT_MIN: %d\n", INT_MIN);
12 | printf("LONG_MAX: %ld\n", LONG_MAX);
13 | printf("LONG_MIN: %ld\n", LONG_MIN);
14 | printf("SCHAR_MAX: %d\n", SCHAR_MAX);
15 | printf("SCHAR_MIN: %d\n", SCHAR_MIN);
16 | printf("SHRT_MAX: %d\n", SHRT_MAX);
17 | printf("SHRT_MIN: %d\n", SHRT_MIN);
18 | printf("UCHAR_MAX: %d\n", UCHAR_MAX);
19 | printf("UINT_MAX: %u\n", UINT_MAX);
20 | printf("ULONG_MAX: %lu\n", ULONG_MAX);
21 | printf("USHRT_MAX: %u\n", USHRT_MAX);
22 |
23 | printf("\nFrom calc:\n");
24 |
25 | /*signed types*/
26 | printf("signed char min=%d\n",-(char)((unsigned char) ~0 >> 1));
27 | printf("signed char max=%d\n",(char)((unsigned char) ~0 >> 1));
28 | printf("signed int min=%d\n",-(int)((unsigned int) ~0 >> 1));
29 | printf("signed int max=%d\n",(int)((unsigned int) ~0 >> 1));
30 | printf("signed short min=%d\n",-(short)((unsigned short) ~0 >> 1));
31 | printf("signed short max=%d\n",(short)((unsigned short) ~0 >> 1));
32 | printf("signed long min=%ld\n",-(long)((unsigned long) ~0 >> 1));
33 | printf("signed long max=%ld\n",(long)((unsigned long) ~0 >> 1));
34 |
35 | /*unsigned types*/
36 | printf("unsigned char max=%u\n",((unsigned char) ~0));
37 | printf("unsigned int max=%u\n",((unsigned int) ~0));
38 | printf("unsigned long max=%lu\n",((unsigned long) ~0));
39 | printf("unsigned short max=%u\n",((unsigned short) ~0));
40 |
41 | }
42 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/10.getbits.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | unsigned getbits(unsigned, int, int);
4 |
5 | main()
6 | {
7 | unsigned a = getbits(255, 3, 4);
8 | printf("%d\n", a);
9 |
10 | unsigned b = getbits(3, 1, 2);
11 | printf("%d\n", b);
12 | }
13 |
14 | unsigned getbits(unsigned x, int p, int n)
15 | {
16 | return (x >> (p+1-n)) & ~(~0 << n);
17 | }
18 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/11.setbits.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int setbits(int, int, int, int);
4 |
5 | main()
6 | {
7 | int a = setbits(255, 0, 4, 0);
8 | printf("%d\n", a);
9 |
10 | int b = setbits(1, 1, 3, 4);
11 | printf("%d\n", b);
12 |
13 | int c = setbits(218, 2, 4, 9);
14 | printf("%d\n", c);
15 | }
16 |
17 | int setbits(int x, int p, int n, int y)
18 | {
19 | x = x & (~((~(~0 << n)) << p));
20 | y = (y & (~(~0 << n))) << p;
21 |
22 | return x | y;
23 | }
24 |
25 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/12.invert.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int invert(int, int, int);
4 |
5 | main()
6 | {
7 | int a = invert(255, 0, 4);
8 | printf("%d\n", a);
9 |
10 | int b = invert(0, 4, 4);
11 | printf("%d\n", b);
12 |
13 | int c = invert(15, 4, 4);
14 | printf("%d\n", c);
15 | }
16 |
17 | int invert(int x, int p, int n)
18 | {
19 | return x ^ (~(~0 << n) << p);
20 | }
21 |
22 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/13.rightrot.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | unsigned rightrot(unsigned, unsigned);
4 |
5 | main()
6 | {
7 | int a = rightrot(255, 32);
8 | printf("%d\n", a);
9 |
10 | int b = rightrot(1, 30);
11 | printf("%d\n", b);
12 | }
13 |
14 | unsigned rightrot(unsigned x, unsigned n)
15 | {
16 | while (n-- > 0) {
17 | if (x & 1 == 1) {
18 | x = (x >> 1) | ~(~0U >> 1);
19 | } else {
20 | x = x >> 1;
21 | }
22 | }
23 |
24 | return x;
25 | }
26 |
27 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/14.bitcount.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int bitcount(unsigned);
4 |
5 | main()
6 | {
7 | printf("%d\n", bitcount(255));
8 | printf("%d\n", bitcount(15));
9 | printf("%d\n", bitcount(1));
10 | printf("%d\n", bitcount(0));
11 | printf("%d\n", bitcount(~0U));
12 | }
13 |
14 | int bitcount(unsigned x)
15 | {
16 | int b;
17 | for (b = 0; x != 0; x >>= 1)
18 | if (x & 01)
19 | b++;
20 |
21 | return b;
22 | }
23 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/15.bitcount2.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int bitcount(unsigned);
4 |
5 | main()
6 | {
7 | printf("%d\n", bitcount(255));
8 | printf("%d\n", bitcount(15));
9 | printf("%d\n", bitcount(1));
10 | printf("%d\n", bitcount(0));
11 | printf("%d\n", bitcount(~0U));
12 | }
13 |
14 | int bitcount(unsigned x)
15 | {
16 | int b = 1;
17 |
18 | if (x == 0)
19 | b--;
20 |
21 | while (x &= (x-1))
22 | b++;
23 |
24 |
25 | return b;
26 | }
27 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/16.lower2.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int lower(int);
4 |
5 | main()
6 | {
7 | printf("%c\n", lower('S'));
8 | printf("%c\n", lower('A'));
9 | printf("%c\n", lower('Z'));
10 | printf("%c\n", lower('a'));
11 | }
12 |
13 | int lower(int c)
14 | {
15 | return (c >= 'A' && c <= 'Z') ? (c + 'a' - 'A') : c;
16 | }
17 |
18 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/2.loop-without-logical-operators.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAXLINE 1024
4 |
5 | int myGetline(char line[], int maxline);
6 | int myGetlineV1(char line[], int maxline);
7 |
8 | main()
9 | {
10 | int len;
11 | char line[MAXLINE];
12 |
13 | while ((len = myGetlineV1(line, MAXLINE)) > 0) {
14 | printf("%s", line);
15 | }
16 |
17 | return 0;
18 | }
19 |
20 | int myGetline(char s[], int lim)
21 | {
22 | int c, i;
23 |
24 | for (i = 0; i < lim - 1 && (c = getchar()) != '\n' && c != EOF; ++i)
25 | s[i] = c;
26 | if (c == '\n') {
27 | s[i] = c;
28 | ++i;
29 | }
30 | s[i] = '\0';
31 | return i;
32 | }
33 |
34 | int myGetlineV1(char s[], int lim)
35 | {
36 | int c, i;
37 |
38 | for (i = 0; i < lim - 1; ++i) {
39 | if ((c = getchar()) == '\n')
40 | break;
41 | if (c == EOF)
42 | break;
43 |
44 | s[i] = c;
45 | }
46 |
47 | if (c == '\n') {
48 | s[i] = c;
49 | ++i;
50 | }
51 | s[i] = '\0';
52 | return i;
53 | }
54 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/3.atoi.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int atoi(char[]);
4 |
5 | main()
6 | {
7 | int a = atoi("1234567890");
8 | printf("%d\n", a);
9 | a = atoi("1234abc567890");
10 | printf("%d\n", a);
11 | }
12 |
13 | int atoi(char s[])
14 | {
15 | int i, n;
16 | n = 0;
17 | for (i = 0; s[i] >= '0' && s[i] <= '9'; ++i)
18 | n = 10 * n + (s[i] - '0');
19 | return n;
20 | }
21 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/4.lower.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int lower(int);
4 |
5 | main()
6 | {
7 | printf("%c\n", lower('S'));
8 | printf("%c\n", lower('A'));
9 | printf("%c\n", lower('Z'));
10 | printf("%c\n", lower('a'));
11 | }
12 |
13 | int lower(int c)
14 | {
15 | if (c >= 'A' && c <= 'Z')
16 | return c + 'a' - 'A';
17 | else
18 | return c;
19 | }
20 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/5.htio.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int htoi(char[]);
4 |
5 | main()
6 | {
7 | int n = htoi("0x123abc");
8 | printf("%d\n", n);
9 | n = htoi("0X123abc");
10 | printf("%d\n", n);
11 | n = htoi("123abc");
12 | printf("%d\n", n);
13 | n = htoi("FF");
14 | printf("%d\n", n);
15 | n = htoi("1F");
16 | printf("%d\n", n);
17 | n = htoi("D");
18 | printf("%d\n", n);
19 | n = htoi("3");
20 | printf("%d\n", n);
21 | n = htoi("3FQWE");
22 | printf("%d\n", n);
23 | }
24 |
25 | int htoi(char s[])
26 | {
27 | int i, n;
28 | n = 0;
29 | for (i = 0; ; ++i) {
30 | if (s[i] == '0' && (s[i+1] == 'x' || s[i+1] == 'X')) {
31 | i++;
32 | continue;
33 | }
34 |
35 | if (s[i] >= '0' && s[i] <= '9') {
36 | n = 16 * n + (s[i] - '0');
37 | } else if (s[i] >= 'a' && s[i] <= 'f') {
38 | n = 16 * n + (s[i] - 'a' + 10);
39 | } else if (s[i] >= 'A' && s[i] <= 'F') {
40 | n = 16 * n + (s[i] - 'A' + 10);
41 | } else {
42 | break;
43 | }
44 | }
45 | return n;
46 | }
47 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/6.squeeze.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | void squeeze(char[], int);
4 |
5 | main()
6 | {
7 | char s[] = "test";
8 | squeeze(s, 't');
9 | printf("%s\n", s);
10 | }
11 |
12 | void squeeze(char s[], int c)
13 | {
14 | int i ,j;
15 |
16 | for (i = j = 0; s[i] != '\0'; i++)
17 | if (s[i] != c)
18 | s[j++] = s[i];
19 |
20 | s[j] = '\0';
21 | }
22 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/7.strcat.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | void strcat(char s[], char t[]);
4 |
5 | main()
6 | {
7 | }
8 |
9 | void strcat(char s[], cahr t[])
10 | {
11 | int i, j;
12 |
13 | i = j = 0;
14 | while (s[i] != '\0')
15 | i++;
16 | while ((s[i++] = t[j++]) != '\0')
17 | ;
18 | }
19 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/8.squeeze2.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | void squeeze(char[], char[]);
4 |
5 | main()
6 | {
7 | char s[] = "test";
8 | char t[] = "te";
9 | squeeze(s, t);
10 | printf("%s\n", s);
11 |
12 | char s1[] = "test";
13 | char t1[] = "st";
14 | squeeze(s1, t1);
15 | printf("%s\n", s1);
16 |
17 | char s2[] = "test";
18 | char t2[] = "sta";
19 | squeeze(s2, t2);
20 | printf("%s\n", s2);
21 |
22 | char s3[] = "test";
23 | char t3[] = "test";
24 | squeeze(s3, t3);
25 | printf("%s\n", s3);
26 |
27 | char s4[] = "test";
28 | char t4[] = "";
29 | squeeze(s4, t4);
30 | printf("%s\n", s4);
31 | }
32 |
33 | void squeeze(char s[], char t[])
34 | {
35 | if (t[0] == '\0')
36 | return;
37 |
38 | int i ,j, k;
39 | int same;
40 |
41 | for (i = j = 0; s[i] != '\0'; i++) {
42 | same = 1;
43 |
44 | for (k = 0; t[k] != '\0'; k++) {
45 | if (s[i+k] == '\0') {
46 | same = 0;
47 | break;
48 | }
49 |
50 |
51 | if (t[k] != s[i+k]) {
52 | same = 0;
53 | break;
54 | }
55 | }
56 |
57 | if (same == 1) {
58 | i += k - 1;
59 | } else {
60 | s[j++] = s[i];
61 | }
62 | }
63 |
64 | s[j] = '\0';
65 | }
66 |
67 |
--------------------------------------------------------------------------------
/chapter-2-types-operators-expressions/9.any.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int any(char[], char[]);
4 |
5 | main()
6 | {
7 | int p;
8 | p = any("test", "test");
9 | printf("p: %d\n", p);
10 |
11 | p = any("test", "es");
12 | printf("p: %d\n", p);
13 |
14 | p = any("test", "s1");
15 | printf("p: %d\n", p);
16 |
17 | p = any("test", "123");
18 | printf("p: %d\n", p);
19 | }
20 |
21 | int any(char s1[], char s2[])
22 | {
23 | int i, j;
24 | int result = -1;
25 |
26 | for(i = 0; s1[i] != '\0'; i++) {
27 | for (j = 0; s2[j] != '\0'; j++) {
28 | if (s1[i] == s2[j]) {
29 | result = i;
30 | break;
31 | }
32 | }
33 |
34 | if (result != -1)
35 | break;
36 | }
37 |
38 | return result;
39 | }
40 |
41 |
--------------------------------------------------------------------------------
/chapter-3-control-flow/01.binsearch.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 |
5 | #define ARRAY_LEN 500000
6 |
7 | int binsearch(int, int[], int);
8 | int binsearchFast(int, int[], int);
9 |
10 | main()
11 | {
12 | clock_t start, finish;
13 | int i, v[ARRAY_LEN];
14 | for (i = 0; i < ARRAY_LEN; i++)
15 | v[i] = i;
16 |
17 | start = clock();
18 | int p;
19 | for (i = 0; i < ARRAY_LEN; i++) {
20 | p = binsearch(i, v, ARRAY_LEN);
21 | //printf("%d at %d\n", i, p);
22 | }
23 | finish = clock();
24 |
25 | printf("binsearch duration: %f\n", ((double)(finish - start)) / CLOCKS_PER_SEC);
26 |
27 | //printf("binsearchFast:\n");
28 |
29 | start = clock();
30 | for (i = 0; i < ARRAY_LEN; i++) {
31 | p = binsearchFast(i, v, ARRAY_LEN);
32 | //printf("%d at %d\n", i, p);
33 | }
34 | finish = clock();
35 | printf("binsearchFast duration: %f\n", ((double)(finish - start)) / CLOCKS_PER_SEC);
36 |
37 | for (i = -10000; i < ARRAY_LEN; i++) {
38 | p = binsearchFast(i, v, ARRAY_LEN);
39 | if (i < 0 && p != -1)
40 | break;
41 | else if (i >= 0 && p != i)
42 | break;
43 | }
44 | printf("i: %d\n", i);
45 | }
46 |
47 | /* binsearch: find x in v[0] <= v[1] <= ... v[n-1] */
48 | int binsearch(int x, int v[], int n)
49 | {
50 | int low, high, mid;
51 |
52 | low = 0;
53 | high = n - 1;
54 | while (low <= high) {
55 | mid = (low + high) / 2;
56 | if (x < v[mid])
57 | high = mid - 1;
58 | else if (x > v[mid])
59 | low = mid + 1;
60 | else
61 | return mid;
62 | }
63 | return -1;
64 | }
65 |
66 | int binsearchFast(int x, int v[], int n)
67 | {
68 | int low, high, mid;
69 |
70 | low = 0;
71 | high = n - 1;
72 | while (low <= high) {
73 | mid = (low + high) / 2;
74 |
75 | if (x <= v[mid])
76 | high = mid - 1;
77 | else
78 | low = mid + 1;
79 | }
80 |
81 | if (x == v[mid])
82 | return mid;
83 | else if (x > v[mid])
84 | mid += 1;
85 | else
86 | mid -= 1;
87 |
88 | if (mid < 0 || mid > n - 1)
89 | return -1;
90 | else
91 | return mid;
92 | }
93 |
--------------------------------------------------------------------------------
/chapter-3-control-flow/02.switch.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | int c, i, nwhite, nother, ndigit[10];
6 |
7 | nwhite = nother = 0;
8 | for (i = 0; i < 10; i++)
9 | ndigit[i] = 0;
10 |
11 | while ((c = getchar()) != EOF) {
12 | switch(c) {
13 | case '0': case '1': case '2': case '3': case '4':
14 | case '5': case '6': case '7': case '8': case '9':
15 | ndigit[c-'0']++;
16 | break;
17 | case ' ':
18 | case '\n':
19 | case '\t':
20 | nwhite++;
21 | break;
22 | default:
23 | nother++;
24 | break;
25 | }
26 | }
27 | printf("digits = ");
28 | for (i = 0; i < 10; i++)
29 | printf(" %d", ndigit[i]);
30 | printf(", white space = %d, other = %d\n",
31 | nwhite, nother);
32 | return 0;
33 | }
34 |
--------------------------------------------------------------------------------
/chapter-3-control-flow/03.escape.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAX_LEN 1000
4 |
5 | void escape(char[], char[]);
6 |
7 | main()
8 | {
9 | char t[] = "Hello\tWorld\r\n\v";
10 | printf("%s\n", t);
11 | char s[MAX_LEN];
12 | escape(s, t);
13 | printf("%s\n", s);
14 | }
15 |
16 | void escape(char s[], char t[])
17 | {
18 | int i, j, n;
19 | for (i = 0, j = 0; t[j] != '\0'; i++, j++) {
20 | switch(t[j]) {
21 | case '\a':
22 | s[i++] = '\\';
23 | n = 'a';
24 | break;
25 | case '\b':
26 | s[i++] = '\\';
27 | n = 'b';
28 | break;
29 | case '\f':
30 | s[i++] = '\\';
31 | n = 'f';
32 | break;
33 | case '\n':
34 | s[i++] = '\\';
35 | n = 'n';
36 | break;
37 | case '\r':
38 | s[i++] = '\\';
39 | n = 'r';
40 | break;
41 | case '\t':
42 | s[i++] = '\\';
43 | n = 't';
44 | break;
45 | case '\v':
46 | s[i++] = '\\';
47 | n = 'v';
48 | break;
49 | default:
50 | n = t[j];
51 | break;
52 | }
53 | s[i] = n;
54 | }
55 | s[i] = '\0';
56 | }
57 |
--------------------------------------------------------------------------------
/chapter-3-control-flow/04.unescape.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAX_LEN 1024
4 |
5 | void unescape(char[], char[]);
6 |
7 | main()
8 | {
9 | char t[] = "Hello\\tWorld!!!\\r\\nEOF\\v";
10 | printf("%s\n", t);
11 | char s[MAX_LEN] = "";
12 | unescape(s, t);
13 | printf("%s\n", s);
14 | }
15 |
16 | void unescape(char s[], char t[])
17 | {
18 | int i, j, n;
19 |
20 | for (i = 0, j = 0; t[j] != '\0'; i++, j++) {
21 | if (t[j] == '\\' && t[j+1] != '\0') {
22 | j++;
23 |
24 | switch(t[j]) {
25 | case 'a':
26 | s[i] = '\a';
27 | break;
28 | case 'b':
29 | s[i] = '\b';
30 | break;
31 | case 'f':
32 | s[i] = '\f';
33 | break;
34 | case 'n':
35 | s[i] = '\n';
36 | break;
37 | case 'r':
38 | s[i] = '\r';
39 | break;
40 | case 't':
41 | s[i] = '\t';
42 | break;
43 | case 'v':
44 | s[i] = '\v';
45 | break;
46 | default:
47 | s[i++] = '\\';
48 | s[i] = t[j];
49 | break;
50 | }
51 | } else {
52 | s[i] = t[j];
53 | }
54 | }
55 |
56 | s[i] = '\0';
57 | }
58 |
59 |
--------------------------------------------------------------------------------
/chapter-3-control-flow/05.atoi.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | main()
5 | {
6 | printf("%d\n", atoi("123"));
7 | printf("%d\n", atoi("+1"));
8 | printf("%d\n", atoi("-0"));
9 | printf("%d\n", atoi("-123"));
10 | printf("%d\n", atoi("asd345"));
11 | printf("%d\n", atoi("789asd345"));
12 | }
13 |
14 | int atoi(char s[])
15 | {
16 | int i, n, sign;
17 |
18 | for (i = 0; isspace(s[i]); i++)
19 | ;
20 |
21 | sign = (s[i] == '-') ? -1 : 1;
22 |
23 | if (s[i] == '+' || s[i] == '-')
24 | i++;
25 |
26 | for (n = 0; isdigit(s[i]); i++)
27 | n = 10 * n + (s[i] - '0');
28 |
29 | return sign * n;
30 | }
31 |
32 |
--------------------------------------------------------------------------------
/chapter-3-control-flow/06.shellsort.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | void shellsort(int [], int);
4 | void printArr(int [], int);
5 |
6 | main()
7 | {
8 | int len = 12;
9 | int v[] = {11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0};
10 | printArr(v, len);
11 | shellsort(v, len);
12 | printArr(v, len);
13 | }
14 |
15 | // sort v[0]...v[n-1] into increasing order
16 | void shellsort(int v[], int n)
17 | {
18 | int gap, i, j, temp;
19 |
20 | for (gap = n / 2; gap > 0; gap /= 2)
21 | for (i = gap; i < n; i++)
22 | for (j = i - gap; j >= 0 && v[j] > v [j + gap]; j -= gap) {
23 | printf("gap: %d, i: %d, j: %d, j+gap: %d\n", gap, i, j, j+gap);
24 | temp = v[j];
25 | v[j] = v[j+gap];
26 | v[j+gap] = temp;
27 | }
28 | }
29 |
30 | void printArr(int v[], int len)
31 | {
32 | int i;
33 | for (i = 0; i < len; i++)
34 | printf("%d ", v[i]);
35 | printf("\n");
36 | }
37 |
--------------------------------------------------------------------------------
/chapter-3-control-flow/07.reverse.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | void reverse(char[]);
5 |
6 | main()
7 | {
8 | char a[] = "Hello, World!";
9 | reverse(a);
10 | printf("%s\n", a);
11 | }
12 |
13 | void reverse(char s[])
14 | {
15 | int c, i, j;
16 |
17 | for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
18 | c = s[i];
19 | s[i] = s[j];
20 | s[j] = c;
21 | }
22 | }
23 |
--------------------------------------------------------------------------------
/chapter-3-control-flow/08.expand.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAX_LEN 1024
4 |
5 | void expand(char s1[], char s2[]);
6 |
7 | main()
8 | {
9 | char s1[] = "-a-z-A-Z-0-9-asd-5-5-5-9a-ZZ-A-G-N-T-Z";
10 | char s2[MAX_LEN];
11 | expand(s1, s2);
12 | printf("%s\n", s2);
13 |
14 | char s[] = "-a-z 0-9 a-d-f -0-2 some text 1-1 WITH CAPITALS! 0-0 5-3 -";
15 | char t[MAX_LEN];
16 | expand(s, t);
17 | printf("%s\n", t);
18 | }
19 |
20 | void expand(char s1[], char s2[])
21 | {
22 | int i, j, k;
23 |
24 | for (i = 0, j = 0; s1[i] != '\0'; i++) {
25 | if (s1[i] == '-' && i > 0 && s1[i+1] != '\0') {
26 | int p = s1[i-1];
27 | int n = s1[i+1];
28 | if (p < n &&
29 | ((p >= 'a' && n <= 'z') || (p >= 'A' && n <= 'Z') || (p >= '0' && n <= '9'))
30 | ) {
31 | for (k = p + 1; k < n; k++)
32 | s2[j++] = k;
33 | } else {
34 | s2[j++] = s1[i];
35 | }
36 | } else {
37 | s2[j++] = s1[i];
38 | }
39 | }
40 |
41 | s2[j] = '\0';
42 | }
43 |
--------------------------------------------------------------------------------
/chapter-3-control-flow/09.itoa.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 |
5 | void itoa(int n, char s[]);
6 | void reverse(char[]);
7 |
8 |
9 | main()
10 | {
11 | int a = 0;
12 | char s[10];
13 | itoa(a, s);
14 | printf("%s\n", s);
15 |
16 | a = INT_MIN;
17 | itoa(a, s);
18 | printf("%s\n", s);
19 |
20 | a = INT_MAX;
21 | itoa(a, s);
22 | printf("%s\n", s);
23 | }
24 |
25 | void itoa(int n, char s[])
26 | {
27 | int i, sign;
28 | int preN = n;
29 | int nIsMinNagetive = n != 0 && n == -n;
30 |
31 | if ((sign = n) < 0) {
32 | if (nIsMinNagetive) {
33 | n += 1;
34 | n = -n;
35 | } else {
36 | n = -n;
37 | }
38 | }
39 |
40 | i = 0;
41 | do {
42 | s[i++] = n % 10 + '0';
43 | } while ((n /= 10) > 0);
44 |
45 | if (sign < 0)
46 | s[i++] = '-';
47 |
48 | s[i] = '\0';
49 | reverse(s);
50 |
51 | if (nIsMinNagetive)
52 | s[strlen(s) - 1] += 1;
53 | }
54 |
55 | void reverse(char s[])
56 | {
57 | int c, i, j;
58 |
59 | for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
60 | c = s[i];
61 | s[i] = s[j];
62 | s[j] = c;
63 | }
64 | }
65 |
--------------------------------------------------------------------------------
/chapter-3-control-flow/10.itob.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 | #include
5 |
6 | #define MAX_LEN 1024
7 |
8 | void itob(int n, char s[], int b);
9 | void itob2(int n, char s[], int b);
10 | void reverse(char[]);
11 |
12 | main()
13 | {
14 | int n = 255;
15 | char s[MAX_LEN];
16 | itob(n, s, 16);
17 | printf("n: %d, s: %s\n", n, s);
18 |
19 | n = INT_MAX;
20 | itob(n, s, 16);
21 | printf("n: %d, s: %s\n", n, s);
22 |
23 | n = 2048;
24 | itob(n, s, 2);
25 | printf("n: %d, s: %s\n", n, s);
26 |
27 | n = 2048;
28 | itob(n, s, 8);
29 | printf("n: %d, s: %s\n", n, s);
30 |
31 | n = INT_MIN;
32 | itob(n, s, 16);
33 | printf("n: %d, s: %s\n", n, s);
34 | }
35 |
36 | void itob(int n, char s[], int b)
37 | {
38 | int i;
39 | int sign = n;
40 |
41 | i = 0;
42 | do {
43 | char c;
44 | int m = abs(n % b);
45 | if (m < 10)
46 | c = m + '0';
47 | else
48 | c = m - 10 + 'a';
49 | s[i++] = c;
50 | } while (n /= b);
51 |
52 | if (sign < 0)
53 | s[i++] = '-';
54 |
55 | s[i] = '\0';
56 | reverse(s);
57 | }
58 |
59 | void reverse(char s[])
60 | {
61 | int c, i, j;
62 |
63 | for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
64 | c = s[i];
65 | s[i] = s[j];
66 | s[j] = c;
67 | }
68 | }
69 |
70 |
--------------------------------------------------------------------------------
/chapter-3-control-flow/11.itoa.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 | #include
5 |
6 | #define MAX_LEN 1024
7 |
8 | void itoa(int n, char s[], int minWidth);
9 | void reverse(char[]);
10 |
11 |
12 | main()
13 | {
14 | int a = 0;
15 | char s[MAX_LEN];
16 | itoa(a, s, 5);
17 | printf("a: %d, %s\n", a, s);
18 |
19 | a = INT_MIN;
20 | itoa(a, s, 20);
21 | printf("INT_MIN: %d, %s\n", a, s);
22 |
23 | a = INT_MAX;
24 | itoa(a, s, 15);
25 | printf("INT_MAX: %d, %s\n", a, s);
26 |
27 | a = 1234567890;
28 | itoa(a, s, 5);
29 | printf("a: %d, %s\n", a, s);
30 | }
31 |
32 | void itoa(int n, char s[], int minWidth)
33 | {
34 | int i;
35 | int sign = n;
36 |
37 | i = 0;
38 | do {
39 | s[i++] = abs(n % 10) + '0';
40 | } while (n /= 10);
41 |
42 | if (sign < 0)
43 | s[i++] = '-';
44 |
45 | int needSpace = minWidth - strlen(s);
46 | while (needSpace-- > 0) {
47 | s[i++] = ' ';
48 | }
49 |
50 | s[i] = '\0';
51 | reverse(s);
52 | }
53 |
54 | void reverse(char s[])
55 | {
56 | int c, i, j;
57 |
58 | for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
59 | c = s[i];
60 | s[i] = s[j];
61 | s[j] = c;
62 | }
63 | }
64 |
65 |
--------------------------------------------------------------------------------
/chapter-3-control-flow/12.trim.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | int trim(char[]);
5 |
6 | main()
7 | {
8 | char s[1024] = "Hello, World ";
9 | trim(s);
10 | printf("%sEOL\n", s);
11 |
12 | s[0] = '\0';
13 | trim(s);
14 | printf("%sEOL\n", s);
15 |
16 | s[0] = ' ', s[1] = ' ', s[2] = '\0';
17 | trim(s);
18 | printf("%sEOL\n", s);
19 |
20 | char a[1024] = "Hello, World 123";
21 | trim(a);
22 | printf("%sEOL\n", a);
23 | }
24 |
25 | int trim(char s[])
26 | {
27 | int n;
28 |
29 | for (n = strlen(s) - 1; n >= 0; n--)
30 | if (s[n] != ' ' && s[n] != '\t' && s[n] != '\n')
31 | break;
32 |
33 | s[n+1] = '\0';
34 | return n;
35 | }
36 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/1.simple-grep.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAXLINE 1000
4 |
5 | int mygetline(char line[], int max);
6 | int strindex(char source[], char searchfor[]);
7 |
8 | char pattern[] = "ould";
9 |
10 | main()
11 | {
12 | char line[MAXLINE];
13 | int found = 0;
14 |
15 | while (mygetline(line, MAXLINE) > 0)
16 | if (strindex(line, pattern) >= 0) {
17 | printf("%s", line);
18 | found++;
19 | }
20 | return found;
21 | }
22 |
23 | int mygetline(char s[], int lim)
24 | {
25 | int c, i;
26 | i =0;
27 | while (--lim > 0 && (c = getchar()) != EOF && c != '\n')
28 | s[i++] = c;
29 | if (c == '\n')
30 | s[i++] = c;
31 | s[i] = '\0';
32 | return i;
33 | }
34 |
35 | int strindex(char s[], char t[])
36 | {
37 | int i, j, k;
38 |
39 | for (i = 0; s[i] != '\0'; i++) {
40 | for (j = i, k = 0; t[k] != '\0' && s[j] == t[k]; j++,k++)
41 | ;
42 | if (k > 0 && t[k] == '\0')
43 | return i;
44 | }
45 | return -1;
46 | }
47 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/10.reverse.recursive.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | void reverse(char [], int, int);
5 | void swap(char s[], int i, int j);
6 |
7 | int main()
8 | {
9 | char s[] = "Hello, World!!!";
10 | reverse(s, 0, strlen(s) - 1);
11 | printf("%s", s);
12 | }
13 |
14 | void reverse(char s[], int left, int right)
15 | {
16 | if (left >= right)
17 | return;
18 |
19 | swap(s, left, right);
20 | reverse(s, ++left, --right);
21 | }
22 |
23 | void swap(char s[], int i, int j)
24 | {
25 | char temp = s[j];
26 | s[j] = s[i];
27 | s[i] = temp;
28 | }
29 |
30 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/11.swap-macro.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define swap(t, x, y) { t temp = x; x = y; y = temp; }
4 |
5 | int main()
6 | {
7 | int x, y;
8 | x = 1;
9 | y = 2;
10 | swap(int, x, y);
11 | printf("%d, %d\n", x, y);
12 |
13 | double a, b;
14 | a = 1.2;
15 | b = -3.9;
16 | swap(double, a, b);
17 | printf("%g, %g\n", a, b);
18 |
19 | return 0;
20 | }
21 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/12.conditional-inclusion.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define SYSTEM 1
4 |
5 | #define BSD 0
6 | #define SYSV 1
7 | #define MSDOC 2
8 |
9 | #ifndef HDR
10 | #if SYSTEM == BSD
11 | #define HDR "bsd.h"
12 | #elif SYSTEM == SYSV
13 | #define HDR "sysv.h"
14 | #elif SYSTEM == MSDOC
15 | #define HDR "msdos.h"
16 | #else
17 | #define HDR "default.h"
18 | #endif
19 |
20 | #include HDR
21 | #endif
22 |
23 | int main()
24 | {
25 | printf("%s\n", OS);
26 | }
27 |
28 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/2.strrindex.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define MAXLINE 1000
5 |
6 | int mygetline(char line[], int max);
7 | int strrindex(char source[], char searchfor[]);
8 |
9 | char pattern[] = "ould";
10 |
11 | main()
12 | {
13 | char line[MAXLINE];
14 | int found = 0;
15 | int p;
16 |
17 | while (mygetline(line, MAXLINE) > 0) {
18 | p = strrindex(line, pattern);
19 | if (p >= 0) {
20 | printf("%s", line);
21 | found++;
22 | }
23 | }
24 | return found;
25 | }
26 |
27 | int mygetline(char s[], int lim)
28 | {
29 | int c, i;
30 | i =0;
31 | while (--lim > 0 && (c = getchar()) != EOF && c != '\n')
32 | s[i++] = c;
33 | if (c == '\n')
34 | s[i++] = c;
35 | s[i] = '\0';
36 | return i;
37 | }
38 |
39 | int strrindex(char s[], char t[])
40 | {
41 | int i, j, k;
42 |
43 | for (i = strlen(s) - 2; i > 0; i--) {
44 | for (j = i, k = strlen(t) - 1; j > 0 && k > 0 && s[j] == t[k]; j--, k--)
45 | ;
46 |
47 | if (k == 0)
48 | return j;
49 | }
50 | return -1;
51 | }
52 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/3.atof-test.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAXLINE 100
4 |
5 | // compile with atof.c, mygetline.c
6 | main()
7 | {
8 | double sum, atof(char []);
9 | char line[MAXLINE];
10 | int mygetline(char line[], int max);
11 |
12 | sum = 0;
13 | while (mygetline(line, MAXLINE) > 0)
14 | printf("\t%g\n", sum += atof(line));
15 | return 0;
16 | }
17 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/4.reverse-polish-calculator.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include // for atof()
4 | #include // for fmod()
5 | #include "calc.h"
6 |
7 | #define MAXOP 100 // max size of operand or operator
8 | #define MAX_VAR_LEN 26 // max size of array for variables
9 |
10 | void mathfunc(char[]);
11 | void setVar(double, double);
12 | void getVar(char[]);
13 |
14 | double variables[MAX_VAR_LEN];
15 | int variableFlags[MAX_VAR_LEN]; // if [0] is 0, means 'a' not set, if [0] is 1, means 'a' set
16 |
17 | // compile with stack.c, getop.c, getch.c
18 | main()
19 | {
20 | int type;
21 | double op2;
22 | char s[MAXOP];
23 |
24 | int i;
25 |
26 | for (i = 0; i < MAX_VAR_LEN; i++)
27 | variableFlags[i] = 0;
28 |
29 | while ((type = getop(s)) != EOF) {
30 | switch(type) {
31 | case NUMBER:
32 | push(atof(s));
33 | break;
34 | case VAR:
35 | getVar(s);
36 | break;
37 | case FUNC:
38 | mathfunc(s);
39 | break;
40 | case '+':
41 | push(pop() + pop());
42 | break;
43 | case '*':
44 | push(pop() * pop());
45 | break;
46 | case '-':
47 | op2 = pop();
48 | push(pop() - op2);
49 | break;
50 | case '/':
51 | op2 = pop();
52 | if (op2 != 0.0)
53 | push(pop() / op2);
54 | else
55 | printf("error: zero divisor\n");
56 | break;
57 | case '%':
58 | op2 = pop();
59 | if (op2 == 0.0)
60 | printf("error: can not mod 0\n");
61 | else
62 | push(fmod(pop(), op2));
63 | break;
64 | case '=':
65 | op2 = pop();
66 | setVar(pop(), op2);
67 | break;
68 | case '\n':
69 | printf("\t%.8g\n", pop());
70 | break;
71 | default:
72 | printf("error: unknown command %s\n", s);
73 | break;
74 | }
75 | }
76 | return 0;
77 | }
78 |
79 | void mathfunc(char s[])
80 | {
81 | int index;
82 | if (0 == strrindex(s, "sin")) {
83 | push(sin(pop()));
84 | return;
85 | }
86 |
87 | if (0 == strrindex(s, "exp")) {
88 | push(exp(pop()));
89 | return;
90 | }
91 |
92 | if (0 == strrindex(s, "pow")) {
93 | double ey = pop();
94 | push(pow(pop(), ey));
95 | return;
96 | }
97 |
98 | printf("error: unknown func %s\n", s);
99 | return;
100 | }
101 |
102 | void setVar(double varIndex, double value)
103 | {
104 | int index = (int)varIndex;
105 | if (index < 0 || index > MAX_VAR_LEN) {
106 | printf("error: cannot set variable, invalid variable: %c\n", index + 'a');
107 | return;
108 | }
109 |
110 | variables[index] = value;
111 | variableFlags[index] = 1;
112 |
113 | push(value); // to show result
114 |
115 | return;
116 | }
117 |
118 | void getVar(char s[])
119 | {
120 | if (strlen(s) != 1 && s[0] != 0) {
121 | // if variable is 'a', s[0] == 0, strlen(s) == 0
122 | printf("error: cannot get variable, invalid variable: %s\n", s);
123 | return;
124 | }
125 |
126 | double value = atof(s);
127 | int index = (int)value;
128 | if (variableFlags[index] == 0)
129 | push(value);
130 | else
131 | push(variables[index]);
132 |
133 | return;
134 | }
135 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/5.getop-with-static.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define BUFSIZE 100
5 | #define MAX_LEN 1024
6 | #define NUMBER '0'
7 |
8 | int getop(char []);
9 |
10 | int main()
11 | {
12 | while (1) {
13 | char s[MAX_LEN];
14 | int op = getop(s);
15 | printf("op: %c\n", op);
16 | }
17 | }
18 |
19 | int getop(char s[])
20 | {
21 | static int buffer = EOF;
22 | printf("buffer: %d\n", buffer);
23 | int i, c;
24 |
25 | while ((s[0] = c = (buffer == EOF ? getchar() : buffer)) == ' ' || c == '\t')
26 | ;
27 |
28 | s[1] = '\0';
29 | if (!isdigit(c) && c != '.')
30 | return c;
31 | i = 0;
32 | if (isdigit(c))
33 | while (isdigit(s[++i] = c = (buffer == EOF ? getchar() : buffer)))
34 | ;
35 |
36 | if (c == '.')
37 | while (isdigit(s[++i] = c = (buffer == EOF ? getchar() : buffer)))
38 | ;
39 | s[i] = '\0';
40 | if (c != EOF) {
41 | if (buffer != EOF)
42 | printf("getop: cannot ungetch more char\n");
43 | else
44 | buffer = c;
45 | }
46 | return NUMBER;
47 | }
48 |
49 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/6.register-variable.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define LOOP_COUNT 1e8
5 |
6 | void withRegister(void);
7 | void withoutRegister(void);
8 |
9 | int main()
10 | {
11 | clock_t start, finish;
12 | start = clock();
13 | withRegister();
14 | finish = clock();
15 | printf("withRegister duration: %f\n", ((double)(finish - start)) / CLOCKS_PER_SEC);
16 |
17 | start = clock();
18 | withoutRegister();
19 | finish = clock();
20 | printf("withoutRegister duration: %f\n", ((double)(finish - start)) / CLOCKS_PER_SEC);
21 | }
22 |
23 | void withRegister(void)
24 | {
25 | register int i;
26 | for (i = 0; i < LOOP_COUNT; i++)
27 | ;
28 |
29 | }
30 |
31 | void withoutRegister(void)
32 | {
33 | int i;
34 | for (i = 0; i < LOOP_COUNT; i++)
35 | ;
36 | }
37 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/7.printd.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | void printd(int n);
4 |
5 | int main()
6 | {
7 | printd(-123456);
8 | }
9 |
10 | void printd(int n)
11 | {
12 | if (n < 0) {
13 | putchar('-');
14 | n = -n;
15 | }
16 | if (n / 10)
17 | printd(n / 10);
18 | putchar(n % 10 + '0');
19 | }
20 |
21 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/8.qsort.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define ARR_LEN 7
4 |
5 | void qsort(int v[], int left, int right);
6 | void printArr(int v[], int len);
7 |
8 | int main()
9 | {
10 | int i;
11 | int v[ARR_LEN] = { 4, 3, 1, 7, 9, 6, 2 };
12 | printArr(v, ARR_LEN);
13 | qsort(v, 0, ARR_LEN-1);
14 | printArr(v, ARR_LEN);
15 | return 0;
16 | }
17 |
18 | void qsort(int v[], int left, int right)
19 | {
20 | int i, last;
21 | void swap(int v[], int i, int j);
22 |
23 | if (left >= right)
24 | return;
25 | swap(v, left, (left + right) / 2);
26 | last = left;
27 | for (i = left+1; i <= right; i++)
28 | if (v[i] < v[left])
29 | swap(v, ++last, i);
30 | swap(v, left, last);
31 | qsort(v, left, last-1);
32 | qsort(v, last+1, right);
33 | }
34 |
35 | void swap(int v[], int i, int j)
36 | {
37 | int temp;
38 |
39 | temp = v[i];
40 | v[i] = v[j];
41 | v[j] = temp;
42 | }
43 |
44 | void printArr(int v[], int len)
45 | {
46 | int i;
47 | for (i = 0; i < len; i++)
48 | printf("%d ", v[i]);
49 | printf("\n");
50 | }
51 |
52 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/9.itoa-recursive.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | void itoa(int n, char s[]);
5 |
6 | int main()
7 | {
8 | char s[1024];
9 | int n = INT_MAX;
10 | itoa(n, s);
11 | printf("s: %s, n: %d\n", s, n);
12 |
13 | n = -2147483647;
14 | itoa(n, s);
15 | printf("s: %s, n: %d\n", s, n);
16 |
17 | n = -INT_MAX;
18 | itoa(n, s);
19 | printf("s: %s, n: %d\n", s, n);
20 |
21 | n = -0;
22 | itoa(n, s);
23 | printf("s: %s, n: %d\n", s, n);
24 |
25 | n = 0;
26 | itoa(n, s);
27 | printf("s: %s, n: %d\n", s, n);
28 |
29 | return 0;
30 | }
31 |
32 | void itoa(int n, char s[])
33 | {
34 | if (n < 0) {
35 | s[0] = '-';
36 | n = -n;
37 | }
38 | if (n / 10)
39 | itoa(n / 10, s);
40 |
41 | int digits = 0;
42 | int t = n;
43 | while (t = t / 10)
44 | digits++;
45 | if (s[0] == '-')
46 | digits++;
47 |
48 | s[digits++] = n % 10 + '0';
49 | s[digits] = '\0';
50 | }
51 |
52 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/atof.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | double atof(char s[])
4 | {
5 | double val, power;
6 | int i, sign;
7 |
8 | for (i = 0; isspace(s[i]); i++)
9 | ;
10 |
11 | sign = (s[i] == '-') ? -1 : 1;
12 | if (s[i] == '+' || s[i] == '-')
13 | i++;
14 |
15 | for (val = 0.0; isdigit(s[i]); i++)
16 | val = 10.0 * val + (s[i] - '0');
17 |
18 | if (s[i] == '.')
19 | i++;
20 |
21 | for (power = 1.0; isdigit(s[i]); i++) {
22 | val = 10.0 * val + (s[i] - '0');
23 | power *= 10.0;
24 | }
25 |
26 | int eSign = 1;
27 | if (s[i] == 'e' || s[i] == 'E') {
28 | if (s[++i] == '-') {
29 | eSign = -1;
30 | i++;
31 | }
32 | }
33 |
34 | double ePower = 1.0;
35 | if (isdigit(s[i])) {
36 | int eCount = s[i] - '0';
37 | while (eCount-- > 0)
38 | ePower *= 10.0;
39 | }
40 |
41 | double result = sign * val / power;
42 |
43 | if (eSign > 0)
44 | result *= ePower;
45 | else
46 | result /= ePower;
47 |
48 | return result;
49 | }
50 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/calc.h:
--------------------------------------------------------------------------------
1 | #define NUMBER '0' // signal that a number was found
2 | #define FUNC '1' // signal that math function was found
3 | #define VAR '2' // signal that variable was found
4 |
5 | void push(double);
6 | double pop(void);
7 |
8 | int getop(char []);
9 |
10 | int getch(void);
11 | void ungetch(int);
12 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/getch.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define BUFSIZE 100
5 |
6 | int buf[BUFSIZE];
7 | int bufp = 0;
8 |
9 | int value = EOF;
10 |
11 | int getch(void)
12 | {
13 | return (bufp > 0) ? buf[--bufp] : getchar();
14 | }
15 |
16 | void ungetch(int c)
17 | {
18 | if (bufp >= BUFSIZE)
19 | printf("ungetch: too many characters\n");
20 | else
21 | buf[bufp++] = c;
22 | }
23 |
24 | void ungetchs(char s[])
25 | {
26 | int len = strlen(s);
27 | while (len > 0) {
28 | ungetch(s[--len]);
29 | }
30 | }
31 |
32 | int getchOne(void)
33 | {
34 | if (value != EOF) {
35 | int temp = value;
36 | value = EOF;
37 | return temp;
38 | }
39 | else
40 | return getchar();
41 | }
42 |
43 | void ungetchOne(int c)
44 | {
45 | if (value != EOF)
46 | printf("ungetchOne: cannot ungetch more char\n");
47 | else
48 | value = c;
49 | }
50 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/getop.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 | #include "calc.h"
5 |
6 | int strrindex(char source[], char searchfor[]);
7 |
8 | int getop(char s[])
9 | {
10 | int i, c;
11 |
12 | while ((s[0] = c = getch()) == ' ' || c == '\t')
13 | ;
14 |
15 | s[1] = '\0';
16 |
17 | i = 0;
18 |
19 | if (c == '+' || c == '-') {
20 | int op = c;
21 | c = getch();
22 | if (!isdigit(c) && c != '.') {
23 | ungetch(c);
24 | return op;
25 | } else {
26 | ungetch(c);
27 | }
28 | } else if (isalpha(c)) {
29 | while (isalpha(s[++i] = c = getch()))
30 | ;
31 | ungetch(c);
32 |
33 | if (i == 1) {
34 | s[0] = tolower(s[0]) - 'a';
35 | s[1] = '\0';
36 | return VAR;
37 | }
38 |
39 | s[++i] = '\0';
40 |
41 | int index;
42 | index = strrindex(s, "sin");
43 | if (index == 0)
44 | return FUNC;
45 |
46 | index = strrindex(s, "exp");
47 | if (index == 0)
48 | return FUNC;
49 |
50 | index = strrindex(s, "pow");
51 | if (index == 0)
52 | return FUNC;
53 |
54 | return 0;
55 | } else if (!isdigit(c) && c != '.') {
56 | return c;
57 | }
58 |
59 | i = 0;
60 |
61 | if (isdigit(c))
62 | while (isdigit(s[++i] = c = getch()))
63 | ;
64 |
65 | if (c == '.')
66 | while (isdigit(s[++i] = c = getch()))
67 | ;
68 |
69 | s[i] = '\0';
70 | if (c != EOF)
71 | ungetch(c);
72 | return NUMBER;
73 | }
74 |
75 | int strrindex(char s[], char t[])
76 | {
77 | int i, j, k;
78 |
79 | for (i = strlen(s) - 2; i > 0; i--) {
80 | for (j = i, k = strlen(t) - 1; j > 0 && k > 0 && s[j] == t[k]; j--, k--)
81 | ;
82 |
83 | if (k == 0)
84 | return j;
85 | }
86 | return -1;
87 | }
88 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/mygetline.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 |
4 | int mygetline(char s[], int lim)
5 | {
6 | int c, i;
7 | i =0;
8 | while (--lim > 0 && (c = getchar()) != EOF && c != '\n')
9 | s[i++] = c;
10 | if (c == '\n')
11 | s[i++] = c;
12 | s[i] = '\0';
13 | return i;
14 | }
15 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/stack.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAXVAL 100
4 |
5 | int sp = 0;
6 | double val[MAXVAL];
7 |
8 | void push(double f)
9 | {
10 | if (sp < MAXVAL)
11 | val[sp++] = f;
12 | else
13 | printf("error: stack full, can't push %g\n", f);
14 | }
15 |
16 | double pop(void)
17 | {
18 | if (sp > 0)
19 | return val[--sp];
20 | else {
21 | printf("error: stack empty\n");
22 | return 0.0;
23 | }
24 | }
25 |
26 | void top(void)
27 | {
28 | if (sp > 0)
29 | printf("stack top: %g\n", val[sp-1]);
30 | else
31 | printf("stack empty\n");
32 | }
33 |
34 | void duplicate(void)
35 | {
36 | if (sp > MAXVAL -1)
37 | printf("error: stack full, can't duplicate\n");
38 | else {
39 | double element = pop();
40 | push(element);
41 | push(element);
42 | }
43 | }
44 |
45 | void swap(void)
46 | {
47 | if (sp < 2)
48 | printf("error: stack size < 2, can't swap\n");
49 | else {
50 | double e1 = pop();
51 | double e2 = pop();
52 | push(e1);
53 | push(e2);
54 | }
55 | }
56 |
57 | void empty(void)
58 | {
59 | sp = 0;
60 | }
61 |
--------------------------------------------------------------------------------
/chapter-4-functions-and-program-structure/sysv.h:
--------------------------------------------------------------------------------
1 | #define OS "sysv"
2 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/1.pointer.c:
--------------------------------------------------------------------------------
1 | int main()
2 | {
3 | int x = 1, y = 2, z[10];
4 | int *ip;
5 |
6 | ip = &x;
7 | y = *ip;
8 | *ip = 0;
9 | ip = &z[0];
10 |
11 | return 0;
12 | }
13 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/10.strcpy-pointer-v1.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int main()
4 | {
5 | void mystrcpy(char*, char*);
6 |
7 | char t[] = "Hello, World!";
8 | char s[100];
9 | mystrcpy(s, t);
10 | printf("%s\n", s);
11 |
12 | return 0;
13 | }
14 |
15 | void mystrcpy(char *s, char *t)
16 | {
17 | while ((*s = *t) != '\0') {
18 | s++;
19 | t++;
20 | }
21 | }
22 |
23 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/11.strcpy-pointer-v2.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int main()
4 | {
5 | void mystrcpy(char*, char*);
6 |
7 | char t[] = "Hello, World!";
8 | char s[100];
9 | mystrcpy(s, t);
10 | printf("%s\n", s);
11 |
12 | return 0;
13 | }
14 |
15 | void mystrcpy(char *s, char *t)
16 | {
17 | while ((*s++ = *t++) != '\0')
18 | ;
19 | }
20 |
21 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/12.strcpy-pointer-v3.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int main()
4 | {
5 | void mystrcpy(char*, char*);
6 |
7 | char t[] = "Hello, World!";
8 | char s[100];
9 | mystrcpy(s, t);
10 | printf("%s\n", s);
11 |
12 | return 0;
13 | }
14 |
15 | void mystrcpy(char *s, char *t)
16 | {
17 | while (*s++ = *t++)
18 | ;
19 | }
20 |
21 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/13.strcmp-array-subscript.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int main()
4 | {
5 | int mystrcmp(char*, char*);
6 |
7 | char *s = "Hello";
8 | char *t = "Hello";
9 | int diff = mystrcmp(s, t);
10 | printf("%d\n", diff);
11 |
12 | return 0;
13 | }
14 |
15 | int mystrcmp(char *s, char *t)
16 | {
17 | int i;
18 |
19 | for (i = 0; s[i] == t[i]; i++)
20 | if (s[i] == '\0')
21 | return 0;
22 | return s[i] - t[i];
23 | }
24 |
25 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/14.strcmp-pointer.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int main()
4 | {
5 | int mystrcmp(char*, char*);
6 |
7 | char *s = "Hello";
8 | char *t = "Hello";
9 | int diff = mystrcmp(s, t);
10 | printf("%d\n", diff);
11 |
12 | return 0;
13 | }
14 |
15 | int mystrcmp(char *s, char *t)
16 | {
17 | for (; *s == *t; s++, t++)
18 | if (*s == '\0')
19 | return 0;
20 | return *s - *t;
21 | }
22 |
23 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/15.strcat-pointer.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int main()
4 | {
5 | void mystrcat(char*, char*);
6 |
7 | char s[100] = "Hello";
8 | char *t = ", World!";
9 | mystrcat(s, t);
10 | printf("%s\n", s);
11 |
12 | return 0;
13 | }
14 |
15 | void mystrcat(char *s, char *t)
16 | {
17 | while (*s)
18 | s++;
19 |
20 | while ((*s++ = *t++))
21 | ;
22 | }
23 |
24 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/16.strend.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int main()
4 | {
5 | int strend(char*, char*);
6 |
7 | char *s = "qweasdzxc123Hello";
8 | char *t = "Hello";
9 | int end = strend(s, t);
10 | printf("%d\n", end);
11 |
12 | return 0;
13 | }
14 |
15 | int strend(char *s, char *t)
16 | {
17 | char *sStart = s;
18 | char *tStart = t;
19 |
20 | while (*s)
21 | s++;
22 |
23 | while (*t)
24 | t++;
25 |
26 | while ((*s-- == *t--) && (t != tStart) & (s != sStart))
27 | ;
28 |
29 | if (t == tStart)
30 | return 1;
31 | else
32 | return 0;
33 | }
34 |
35 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/17.strncpy.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | int main()
5 | {
6 | char *mystrncpy(char*, char *, int);
7 |
8 | char s[100];
9 | char *ct = "hello, world!";
10 | char *t = mystrncpy(s, ct, 5);
11 | printf("%s\n", s);
12 | printf("%s\n", t);
13 |
14 | t = strncpy(s, ct, 8);
15 | printf("%s\n", t);
16 |
17 | return 0;
18 | }
19 |
20 | char *mystrncpy(char *s, char *ct, int n)
21 | {
22 | char *start = s;
23 | for (; n > 0 && *ct != '\0'; n--) {
24 | *s++ = *ct++;
25 | }
26 |
27 | while (n-- > 0)
28 | *s++ = '\0';
29 |
30 | return start;
31 | }
32 |
33 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/18.strncat.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | int main()
5 | {
6 | char *mystrncat(char*, char *, int);
7 |
8 | char s[100] = "Hello, ";
9 | char *ct = "world!";
10 | char *t = mystrncat(s, ct, 5);
11 | printf("%s\n", s);
12 | printf("%s\n", t);
13 |
14 | t = strncat(s, ct, 8);
15 | printf("%s\n", t);
16 |
17 | return 0;
18 | }
19 |
20 | char *mystrncat(char *s, char *ct, int n)
21 | {
22 | char *ts = s;
23 | while (*++ts)
24 | ;
25 |
26 | for (; n > 0 && ct != '\0'; n--)
27 | *ts++ = *ct++;
28 |
29 | *ts = '\0';
30 |
31 | return s;
32 | }
33 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/19.strncmp.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | int main()
5 | {
6 | int mystrncmp(char *, char *, int);
7 |
8 | char *s = "Hellp";
9 | char *t = "Hello";
10 | int diff = mystrncmp(s, t, 5);
11 | printf("%d\n", diff);
12 |
13 | diff = strncmp(s, t, 5);
14 | printf("%d\n", diff);
15 |
16 | return 0;
17 | }
18 |
19 | int mystrncmp(char *cs, char *ct, int n)
20 | {
21 | for (; *cs == *ct && n > 0; cs++, ct++)
22 | if (*cs == '\0')
23 | return 0;
24 |
25 | if (n == 0)
26 | return 0;
27 |
28 | return *cs - *ct;
29 | }
30 |
31 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/2.swap.c:
--------------------------------------------------------------------------------
1 | int main()
2 | {
3 | }
4 |
5 | void swap(int *px, int *py)
6 | {
7 | int temp;
8 |
9 | temp = *px;
10 | *px = *py;
11 | *py = temp;
12 | }
13 |
14 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/20.getline-pointer.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int main()
4 | {
5 | int mygetline(char *, int);
6 | char s[100];
7 | int len = mygetline(s, 100);
8 | printf("%d %s\n", len, s);
9 |
10 | return 0;
11 | }
12 |
13 | int mygetline(char *s, int lim)
14 | {
15 | int c;
16 | char *t = s;
17 | while (--lim > 0 && (c = getchar()) != EOF && c != '\n')
18 | *s++ = c;
19 |
20 | if (c == '\n')
21 | *s++ = c;
22 |
23 | *s = '\0';
24 | return s - t - 1;
25 | }
26 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/21.atoi.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | int main()
5 | {
6 | printf("%d\n", atoi("123"));
7 | printf("%d\n", atoi("+1"));
8 | printf("%d\n", atoi("-0"));
9 | printf("%d\n", atoi("-123"));
10 | printf("%d\n", atoi("asd345"));
11 | printf("%d\n", atoi("789asd345"));
12 |
13 | return 0;
14 | }
15 |
16 | int atoi(char *s)
17 | {
18 | int sign, n;
19 |
20 | while (isspace(*s))
21 | s++;
22 |
23 | sign = (*s == '-') ? -1 : 1;
24 |
25 | if (*s == '+' || *s == '-')
26 | s++;
27 |
28 | n = 0;
29 | while (isdigit(*s))
30 | n = 10 * n + (*s++ - '0');
31 |
32 | return sign * n;
33 | }
34 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/22.itoa.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 | #include
5 |
6 | int main()
7 | {
8 | void itoa(int, char*);
9 |
10 | int n = 0;
11 | char s[10];
12 | itoa(n, s);
13 | printf("%d to %s\n", n, s);
14 |
15 | n = -0;
16 | itoa(n, s);
17 | printf("%d to %s\n", n, s);
18 |
19 | n = 1234;
20 | itoa(n, s);
21 | printf("%d to %s\n", n, s);
22 |
23 | n = INT_MIN;
24 | itoa(n, s);
25 | printf("%d to %s\n", n, s);
26 |
27 | n = INT_MAX;
28 | itoa(n, s);
29 | printf("%d to %s\n", n, s);
30 |
31 | return 0;
32 | }
33 |
34 | void itoa(int n, char *s)
35 | {
36 | void reverse(char*);
37 |
38 | char *p = s;
39 | int sign = n;
40 |
41 | do {
42 | *s++ = abs(n % 10) + '0';
43 | } while (n /= 10);
44 |
45 | if (sign < 0)
46 | *s++ = '-';
47 |
48 |
49 | *s = '\0';
50 | reverse(p);
51 | }
52 |
53 | void reverse(char *s)
54 | {
55 | char *t = s + strlen(s) - 1;
56 | char c;
57 |
58 | while (s < t) {
59 | c = *s;
60 | *s = *t;
61 | *t = c;
62 | s++;
63 | t--;
64 | }
65 | }
66 |
67 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/23.pointer-arrays.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 |
5 | #define MAXLINES 50000
6 |
7 | char *lineptr[MAXLINES];
8 |
9 | int readlines(char *lineptr[], int nlines);
10 | void writelines(char *lineptr[], int nlines);
11 |
12 | void qsort(char *lineptr[], int left, int right);
13 |
14 | int main()
15 | {
16 | int nlines;
17 |
18 | if ((nlines = readlines(lineptr, MAXLINES)) >= 0) {
19 | qsort(lineptr, 0, nlines-1);
20 | //writelines(lineptr, nlines);
21 | return 0;
22 | } else {
23 | printf("error: input too big to sort\n");
24 | return 1;
25 | }
26 |
27 | return 0;
28 | }
29 |
30 | #define MAXLEN 1000
31 |
32 | int mygetline(char *, int);
33 | char *alloc(int);
34 |
35 | int readlines(char *lineptr[], int maxlines)
36 | {
37 | clock_t start, finish;
38 | start = clock();
39 |
40 | int len, nlines;
41 | char *p, line[MAXLEN];
42 | nlines = 0;
43 | while ((len = mygetline(line, MAXLEN)) > 0)
44 | if (nlines >= maxlines || (p = alloc(len)) == NULL)
45 | return -1;
46 | else {
47 | line[len-1] = '\0';
48 | strcpy(p, line);
49 | lineptr[nlines++] = p;
50 | }
51 |
52 | finish = clock();
53 | printf("alloc: %f\n", ((double)(finish - start)) / CLOCKS_PER_SEC);
54 | return nlines;
55 | }
56 |
57 | void writelines(char *lineptr[], int nlines)
58 | {
59 | while (nlines-- > 0)
60 | printf("%s\n", *lineptr++);
61 | }
62 |
63 | int mygetline(char *s, int lim)
64 | {
65 | int c;
66 | char *t = s;
67 | while (--lim > 0 && (c = getchar()) != EOF && c != '\n')
68 | *t++ = c;
69 |
70 | if (c == '\n')
71 | *t++ = c;
72 |
73 | *t = '\0';
74 | return t - s;
75 | }
76 |
77 | void qsort(char *v[], int left, int right)
78 | {
79 | int i, last;
80 | void swap(char *v[], int i, int j);
81 | if (left >= right)
82 | return;
83 | swap(v, left, (left + right)/2);
84 | last = left;
85 | for (i = left+1; i <= right; i++)
86 | if (strcmp(v[i], v[left]) < 0)
87 | swap(v, ++last, i);
88 | swap(v, left, last);
89 | qsort(v, left, last-1);
90 | qsort(v, last+1, right);
91 | }
92 |
93 | void swap(char *v[], int i, int j)
94 | {
95 | char *temp;
96 |
97 | temp = v[i];
98 | v[i] = v[j];
99 | v[j] = temp;
100 | }
101 |
102 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/24.pointer-arrays-without-alloc.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 |
5 | #define MAXLINES 50000
6 |
7 | #define ARR_SIZE 1000000
8 |
9 | char strstore[ARR_SIZE];
10 |
11 | char *lineptr[MAXLINES];
12 |
13 | int readlines(char *lineptr[], int nlines);
14 | void writelines(char *lineptr[], int nlines);
15 |
16 | void qsort(char *lineptr[], int left, int right);
17 |
18 | int main()
19 | {
20 | int nlines;
21 |
22 | if ((nlines = readlines(lineptr, MAXLINES)) >= 0) {
23 | qsort(lineptr, 0, nlines-1);
24 | //writelines(lineptr, nlines);
25 | return 0;
26 | } else {
27 | printf("error: input too big to sort\n");
28 | return 1;
29 | }
30 |
31 | return 0;
32 | }
33 |
34 | #define MAXLEN 1000
35 |
36 | int mygetline(char *, int);
37 | char *alloc(int);
38 |
39 | int readlines(char *lineptr[], int maxlines)
40 | {
41 | clock_t start, finish;
42 | start = clock();
43 |
44 | int len, nlines;
45 | int offset = 0;
46 | char *p, line[MAXLEN];
47 | nlines = 0;
48 | while ((len = mygetline(line, MAXLEN)) > 0)
49 | if (nlines >= maxlines || (p = &strstore[offset]) == NULL)
50 | return -1;
51 | else {
52 | line[len-1] = '\0';
53 | strcpy(p, line);
54 | offset += len;
55 | lineptr[nlines++] = p;
56 | }
57 |
58 | finish = clock();
59 | printf("without alloc: %f\n", ((double)(finish - start)) / CLOCKS_PER_SEC);
60 | return nlines;
61 | }
62 |
63 | void writelines(char *lineptr[], int nlines)
64 | {
65 | while (nlines-- > 0)
66 | printf("%s\n", *lineptr++);
67 | }
68 |
69 | int mygetline(char *s, int lim)
70 | {
71 | int c;
72 | char *t = s;
73 | while (--lim > 0 && (c = getchar()) != EOF && c != '\n')
74 | *t++ = c;
75 |
76 | if (c == '\n')
77 | *t++ = c;
78 |
79 | *t = '\0';
80 | return t - s;
81 | }
82 |
83 | void qsort(char *v[], int left, int right)
84 | {
85 | int i, last;
86 | void swap(char *v[], int i, int j);
87 | if (left >= right)
88 | return;
89 | swap(v, left, (left + right)/2);
90 | last = left;
91 | for (i = left+1; i <= right; i++)
92 | if (strcmp(v[i], v[left]) < 0)
93 | swap(v, ++last, i);
94 | swap(v, left, last);
95 | qsort(v, left, last-1);
96 | qsort(v, last+1, right);
97 | }
98 |
99 | void swap(char *v[], int i, int j)
100 | {
101 | char *temp;
102 |
103 | temp = v[i];
104 | v[i] = v[j];
105 | v[j] = temp;
106 | }
107 |
108 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/25.year-month-day.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | static char daytab[2][13] = {
4 | {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
5 | {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
6 | };
7 |
8 | int main()
9 | {
10 | int day_of_year(int, int, int);
11 | void month_day(int, int, int*, int*);
12 |
13 | int day = day_of_year(2018, 8, 19);
14 | printf("%d\n", day);
15 |
16 | day = day_of_year(2018, 13, 19);
17 | printf("%d\n", day);
18 |
19 | day = day_of_year(2018, 12, 39);
20 | printf("%d\n", day);
21 |
22 | day = day_of_year(2018, 12, 0);
23 | printf("%d\n", day);
24 |
25 | int month;
26 | month_day(2018, 231, &month, &day);
27 | printf("%d, %d\n", month, day);
28 |
29 | month_day(2018, -1, &month, &day);
30 | printf("%d, %d\n", month, day);
31 |
32 | month_day(2018, 1234, &month, &day);
33 | printf("%d, %d\n", month, day);
34 |
35 | month_day(2018, 365, &month, &day);
36 | printf("%d, %d\n", month, day);
37 |
38 | month_day(2018, 366, &month, &day);
39 | printf("%d, %d\n", month, day);
40 |
41 | month_day(2016, 366, &month, &day);
42 | printf("%d, %d\n", month, day);
43 |
44 | return 0;
45 | }
46 |
47 | int day_of_year(int year, int month, int day)
48 | {
49 | int i, leap;
50 | if (month < 1 || month > 12) {
51 | printf("error: invalid month: %d\n", month);
52 | return -1;
53 | }
54 |
55 | leap = year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
56 |
57 | if (day < 1 || day > daytab[leap][month]) {
58 | printf("error: invalid day: %d\n", day);
59 | return -1;
60 | }
61 |
62 | for (i = 1; i < month; i++)
63 | day += daytab[leap][i];
64 | return day;
65 | }
66 |
67 | void month_day(int year, int yearday, int *pmonth, int *pday)
68 | {
69 | int i, leap;
70 | leap = year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
71 | if (yearday < 1) {
72 | printf("error: invalid yearday: %d\n", yearday);
73 | return;
74 | } else if (leap == 1 && yearday > 366) {
75 | printf("error: invalid yearday: %d\n", yearday);
76 | return;
77 | } else if (leap == 0 && yearday > 365) {
78 | printf("error: invalid yearday: %d\n", yearday);
79 | return;
80 | }
81 |
82 | for (i = 1; yearday > daytab[leap][i]; i++)
83 | yearday -= daytab[leap][i];
84 | *pmonth = i;
85 | *pday = yearday;
86 | }
87 |
88 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/26.pointer-array-init.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int main()
4 | {
5 | char *month_name(int);
6 |
7 | char *n = month_name(9);
8 | printf("%s\n", n);
9 |
10 | return 0;
11 | }
12 |
13 | char *month_name(int n)
14 | {
15 | static char *name[] = {
16 | "Illegal month",
17 | "January", "February", "March",
18 | "Aprial", "May", "June",
19 | "July", "August", "September",
20 | "October", "November", "December"
21 | };
22 |
23 | return (n < 1 || n > 12) ? name[0] : name[n];
24 | }
25 |
26 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/27.year-month-day-pointer.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | char a[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
4 | char b[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
5 |
6 | static char *daytab[2] = {a, b};
7 | /*
8 | static char *daytab[2] = {
9 | {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
10 | {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
11 | };
12 | */
13 |
14 | char *name[] = {"Jan", "Feb"};
15 | char n0[][10] = { {"Jan"}, {"Feb"} };
16 | char n1[][10] = { "Jan", "Feb" };
17 | //char *n2[] = { {"Jan"}, {"Feb"} };
18 |
19 | int main()
20 | {
21 | int day_of_year(int, int, int);
22 | void month_day(int, int, int*, int*);
23 |
24 | int day = day_of_year(2018, 8, 19);
25 | printf("%d\n", day);
26 |
27 | day = day_of_year(2018, 13, 19);
28 | printf("%d\n", day);
29 |
30 | day = day_of_year(2018, 12, 39);
31 | printf("%d\n", day);
32 |
33 | day = day_of_year(2018, 12, 0);
34 | printf("%d\n", day);
35 |
36 | int month;
37 | month_day(2018, 231, &month, &day);
38 | printf("%d, %d\n", month, day);
39 |
40 | month_day(2018, -1, &month, &day);
41 | printf("%d, %d\n", month, day);
42 |
43 | month_day(2018, 1234, &month, &day);
44 | printf("%d, %d\n", month, day);
45 |
46 | month_day(2018, 365, &month, &day);
47 | printf("%d, %d\n", month, day);
48 |
49 | month_day(2018, 366, &month, &day);
50 | printf("%d, %d\n", month, day);
51 |
52 | month_day(2016, 366, &month, &day);
53 | printf("%d, %d\n", month, day);
54 |
55 | return 0;
56 | }
57 |
58 | int day_of_year(int year, int month, int day)
59 | {
60 | int i, leap;
61 | if (month < 1 || month > 12) {
62 | printf("error: invalid month: %d\n", month);
63 | return -1;
64 | }
65 |
66 | leap = year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
67 |
68 | if (day < 1 || day > daytab[leap][month]) {
69 | printf("error: invalid day: %d\n", day);
70 | return -1;
71 | }
72 |
73 | char *p = daytab[leap] + 1;
74 |
75 | for (i = 1; i < month; i++)
76 | day += *p++;
77 | return day;
78 | }
79 |
80 | void month_day(int year, int yearday, int *pmonth, int *pday)
81 | {
82 | int i, leap;
83 | leap = year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
84 | if (yearday < 1) {
85 | printf("error: invalid yearday: %d\n", yearday);
86 | return;
87 | } else if (leap == 1 && yearday > 366) {
88 | printf("error: invalid yearday: %d\n", yearday);
89 | return;
90 | } else if (leap == 0 && yearday > 365) {
91 | printf("error: invalid yearday: %d\n", yearday);
92 | return;
93 | }
94 |
95 | char *p = daytab[leap] + 1;
96 |
97 | for (i = 1; yearday > *p; i++)
98 | yearday -= *p++;
99 | *pmonth = i;
100 | *pday = yearday;
101 | }
102 |
103 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/28.echo-v1.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main(int argc, char *argv[])
4 | {
5 | int i;
6 |
7 | for (i = 1; i < argc; i++)
8 | printf("%s%s", argv[i], (i < argc-1) ? " " : "");
9 | printf("\n");
10 |
11 | return 0;
12 | }
13 |
14 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/29.echo-v2.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main(int argc, char *argv[])
4 | {
5 | while (--argc > 0)
6 | printf("%s%s", *++argv, (argc > 1) ? " " : "");
7 | //printf((argc > 1) ? "%s " : "%s", *++argv);
8 | printf("\n");
9 |
10 | return 0;
11 | }
12 |
13 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/3.getint.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define SIZE 10
5 |
6 | int getch(void);
7 | void ungetch(int);
8 |
9 | // compile with getch.c
10 | int main()
11 | {
12 | int n, array[SIZE], getint(int *);
13 |
14 | for (n = 0; n < SIZE; n++)
15 | array[n] = 0;
16 |
17 | for (n = 0; n < SIZE && getint(&array[n]) != EOF; n++)
18 | ;
19 |
20 | for (n = 0; n < SIZE; n++)
21 | printf("%d ", array[n]);
22 |
23 | printf("\n");
24 | return 0;
25 | }
26 |
27 | int getint(int *pn)
28 | {
29 | int c, sign;
30 |
31 | while (isspace(c = getch()))
32 | ;
33 |
34 | if (!isdigit(c) && c != EOF && c != '+' && c != '-') {
35 | ungetch(c);
36 | return 0;
37 | }
38 | sign = (c == '-') ? -1 : 1;
39 | if (c == '+' || c == '-') {
40 | c = getch();
41 | if (!isdigit(c)) {
42 | ungetch(sign == 1 ? '+' : '-');
43 | return 0;
44 | }
45 | }
46 | for (*pn = 0; isdigit(c); c = getch())
47 | *pn = 10 * *pn + (c - '0');
48 | *pn *= sign;
49 | if (c != EOF)
50 | ungetch(c);
51 | return c;
52 | }
53 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/30.find.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #define MAXLINE 1000
4 |
5 | int mygetline(char *line, int max);
6 |
7 | main(int argc, char *argv[])
8 | {
9 | char line[MAXLINE];
10 | int found = 0;
11 |
12 | if (argc != 2)
13 | printf("Usage: find pattern\n");
14 | else
15 | while (mygetline(line, MAXLINE) > 0)
16 | if (strstr(line, argv[1]) != NULL) {
17 | printf("%s", line);
18 | found++;
19 | }
20 | return found;
21 | }
22 |
23 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/31.find.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define MAXLINE 1000
5 |
6 | int mygetline(char *line, int max);
7 |
8 | main(int argc, char *argv[])
9 | {
10 | char line[MAXLINE];
11 | long lineno = 0;
12 | int c, except = 0, number = 0, found = 0;
13 |
14 | while (--argc > 0 && (*++argv)[0] == '-')
15 | while (c = *++argv[0])
16 | switch(c) {
17 | case 'x':
18 | except = 1;
19 | break;
20 | case 'n':
21 | number = 1;
22 | break;
23 | default:
24 | printf("find: illegal option %c\n", c);
25 | argc = 0;
26 | found = -1;
27 | break;
28 | }
29 | if (argc != 1)
30 | printf("Usage: find -x -n pattern\n");
31 | else
32 | while (mygetline(line, MAXLINE) > 0) {
33 | lineno++;
34 | if ((strstr(line, *argv) != NULL) != except) {
35 | if (number)
36 | printf("%ld:", lineno);
37 | printf("%s", line);
38 | found++;
39 | }
40 | }
41 | return found;
42 | }
43 |
44 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/32.expr.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define MAXOP 100
5 | #define NUMBER '0'
6 |
7 | int getop(char [], int, char **);
8 | void push(double);
9 | double pop(void);
10 |
11 | main(int argc, char **argv)
12 | {
13 | int type;
14 | double op2;
15 | char s[MAXOP];
16 |
17 | if (argc == 1) {
18 | printf("Usage: expr 1 1 +\n");
19 | return 1;
20 | }
21 |
22 | while ((type = getop(s, --argc, ++argv)) != EOF) {
23 | switch (type) {
24 | case NUMBER:
25 | push(atof(s));
26 | break;
27 | case '+':
28 | push(pop() + pop());
29 | break;
30 | case '*':
31 | push(pop() * pop());
32 | break;
33 | case '-':
34 | op2 = pop();
35 | push(pop() - op2);
36 | break;
37 | case '/':
38 | op2 = pop();
39 | if (op2 != 0.0)
40 | push(pop() / op2);
41 | else
42 | printf("error: zero divisor\n");
43 | break;
44 | default:
45 | printf("error: unknown command %s\n", s);
46 | break;
47 | }
48 | }
49 |
50 | printf("Result: %g\n", pop());
51 |
52 | return 0;
53 | }
54 |
55 |
56 | #define MAXVAL 100
57 |
58 | int sp = 0;
59 | double val[MAXVAL];
60 |
61 | void push(double f)
62 | {
63 | if (sp < MAXVAL)
64 | val[sp++] = f;
65 | else
66 | printf("error: stack full, can't push %g\n", f);
67 | }
68 |
69 | double pop(void)
70 | {
71 | if (sp > 0)
72 | return val[--sp];
73 | else {
74 | printf("error: stack empty\n");
75 | return 0.0;
76 | }
77 | }
78 |
79 | int getop(char *s, int argc, char **argv)
80 | {
81 | if (argc == 0)
82 | return EOF;
83 |
84 | char *param = *argv;
85 |
86 | int c;
87 |
88 | while ((*s = c = *param++) == ' ' || c == '\t')
89 | ;
90 |
91 | *++s = '\0';
92 |
93 | if (!isdigit(c) && c != '.')
94 | return c;
95 |
96 | if (isdigit(c))
97 | while (isdigit(*s++ = c = *param++))
98 | ;
99 |
100 |
101 | if (c == '.')
102 | while (isdigit(*s++ = c = *param++))
103 | ;
104 |
105 | *s = '\0';
106 |
107 | return NUMBER;
108 | }
109 |
110 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/33.detab.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main(int argc, char *argv[])
4 | {
5 | int c, n, i;
6 | int cur;
7 |
8 | if (argc == 1)
9 | n = 8;
10 | else if (argc == 2)
11 | n = atoi(*++argv);
12 | else {
13 | printf("Usage: detab (8)(tab stop)\n");
14 | return 1;
15 | }
16 |
17 | cur = 0;
18 |
19 | while ((c = getchar()) != EOF) {
20 | if (c == '\t') {
21 | for (i = n - cur; i > 0; --i)
22 | putchar(' ');
23 |
24 | cur = 0;
25 | } else {
26 | putchar(c);
27 | ++cur;
28 | if (cur >= n || c == '\n')
29 | cur = 0;
30 | }
31 | }
32 | }
33 |
34 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/34.entab.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define MAXLINE 1000
4 |
5 | int myGetline(char line[], int maxline);
6 |
7 | main(int argc, char *argv[])
8 | {
9 | int c, len;
10 | int i;
11 | char line[MAXLINE];
12 | int tabstop;
13 | int spaceCount;
14 |
15 | if (argc == 1)
16 | tabstop = 8;
17 | else if (argc == 2)
18 | tabstop = atoi(*++argv);
19 | else {
20 | printf("Usage entab (8)(tabstop)\n");
21 | return 1;
22 | }
23 |
24 | while ((len = myGetline(line, MAXLINE)) > 0) {
25 | spaceCount = 0;
26 |
27 | for (i = 0; i < len; ++i) {
28 | if (line[i] == ' ')
29 | spaceCount++;
30 | else
31 | spaceCount = 0;
32 |
33 | if (spaceCount == tabstop) {
34 | }
35 | }
36 | printf("%s", line);
37 | }
38 | }
39 |
40 | int myGetline(char s[], int lim)
41 | {
42 | int c, i;
43 |
44 | for (i = 0; i < lim - 1 && (c = getchar()) != EOF && c != '\n'; ++i)
45 | s[i] = c;
46 | if (c == '\n') {
47 | s[i] = c;
48 | ++i;
49 | }
50 | s[i] = '\0';
51 | return i;
52 | }
53 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/35.detab-arg.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main(int argc, char *argv[])
4 | {
5 | }
6 |
7 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/36.entab-arg.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main(int argc, char *argv[])
4 | {
5 | }
6 |
7 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/37.tail.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define MAXLINES 50000
5 | #define MAXLEN 10000
6 |
7 | int mygetline(char *line, int max);
8 |
9 | char *alloc(int);
10 | void afree(char*);
11 |
12 | main(int argc, char *argv[])
13 | {
14 | int n;
15 |
16 | if (argc == 1)
17 | n = 10;
18 | else if (argc == 2 && (*++argv)[0] == '-') {
19 | n = atoi(*argv + 1);
20 | if (n < 1)
21 | n = 10;
22 | } else {
23 | printf("Usage: tail -n\n");
24 | return 1;
25 | }
26 |
27 | char line[MAXLEN], *lineptr[MAXLINES];
28 | int len;
29 | char *p;
30 | int lines = 0;
31 |
32 | while ((len = mygetline(line, MAXLEN)) > 0) {
33 | p = alloc(len + 1);
34 | strcpy(p, line);
35 | lineptr[lines++] = p;
36 | }
37 |
38 |
39 | int i = lines - n;
40 | i = (i >= 0) ? i : 0;
41 |
42 | while (n-- > 0 && i <= lines) {
43 | printf("%s", lineptr[i++]);
44 | }
45 |
46 | return 0;
47 | }
48 |
49 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/38.pointers-to-functions.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define MAXLINES 5000
5 | char *lineptr[MAXLINES];
6 |
7 | int readlines(char *lineptr[], int nlines);
8 | void writelines(char *lineptr[], int nlines);
9 |
10 | void qsort(void *lineptr[], int left, int right,
11 | int (*comp)(void *, void *));
12 |
13 | int numcmp(const char *, const char *);
14 |
15 | // gcc 38.pointers-to-functions.c numcmp.c readlines-writelines.c 6.alloc.c
16 | main(int argc, char *argv[])
17 | {
18 | int nlines;
19 | int numeric = 0;
20 |
21 | if (argc > 1 && strcmp(argv[1], "-n") == 0)
22 | numeric = 1;
23 | if ((nlines = readlines(lineptr, MAXLINES)) >= 0) {
24 | qsort((void **) lineptr, 0, nlines-1,
25 | (int (*)(void*, void*))(numeric ? numcmp : strcmp));
26 | writelines(lineptr, nlines);
27 | return 0;
28 | } else {
29 | printf("input too big to sort\n");
30 | return 1;
31 | }
32 | }
33 |
34 | void qsort(void *v[], int left, int right,
35 | int (*comp)(void *, void *))
36 | {
37 | int i, last;
38 | void swap(void *v[], int, int);
39 |
40 | if (left >= right)
41 | return;
42 | swap(v, left, (left + right)/2);
43 | last = left;
44 | for (i = left+1; i <= right; i++)
45 | if ((*comp)(v[i], v[left]) < 0)
46 | swap(v, ++last, i);
47 | swap(v, left, last);
48 | qsort(v, left, last-1, comp);
49 | qsort(v, last+1, right, comp);
50 | }
51 |
52 | void swap(void *v[], int i, int j)
53 | {
54 | void *temp;
55 | temp = v[i];
56 | v[i] = v[j];
57 | v[j] = temp;
58 | }
59 |
60 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/39.sort-with-r.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define MAXLINES 5000
5 | char *lineptr[MAXLINES];
6 |
7 | int readlines(char *lineptr[], int nlines);
8 | void writelines(char *lineptr[], int nlines);
9 |
10 | void qsort(void *lineptr[], int left, int right,
11 | int reverse, int (*comp)(void *, void *));
12 |
13 | int numcmp(const char *, const char *);
14 |
15 | // gcc 39.sort-with-r.c numcmp.c readlines-writelines.c 6.alloc.c
16 | main(int argc, char *argv[])
17 | {
18 | char c;
19 | int nlines;
20 | int numeric = 0;
21 | int reverse = 0;
22 |
23 | while (--argc > 0 && (*++argv)[0] == '-')
24 | while (c = *++argv[0])
25 | switch(c) {
26 | case 'n':
27 | numeric = 1;
28 | break;
29 | case 'r':
30 | reverse = 1;
31 | break;
32 | default:
33 | printf("find illegal option %c\n", c);
34 | return 1;
35 | }
36 |
37 | if (argc != 0) {
38 | printf("Usage: sort -n -r\n");
39 | return 1;
40 | }
41 |
42 | if ((nlines = readlines(lineptr, MAXLINES)) >= 0) {
43 | qsort((void **) lineptr, 0, nlines-1, reverse,
44 | (int (*)(void*, void*))(numeric ? numcmp : strcmp));
45 | writelines(lineptr, nlines);
46 | return 0;
47 | } else {
48 | printf("input too big to sort\n");
49 | return 1;
50 | }
51 | }
52 |
53 | void qsort(void *v[], int left, int right,
54 | int reverse, int (*comp)(void *, void *))
55 | {
56 | int i, last;
57 | void swap(void *v[], int, int);
58 |
59 | if (left >= right)
60 | return;
61 | swap(v, left, (left + right)/2);
62 | last = left;
63 | for (i = left+1; i <= right; i++) {
64 | if (reverse && ((*comp)(v[i], v[left]) > 0))
65 | swap(v, ++last, i);
66 | else if (!reverse && ((*comp)(v[i], v[left]) < 0))
67 | swap(v, ++last, i);
68 | }
69 | swap(v, left, last);
70 | qsort(v, left, last-1, reverse, comp);
71 | qsort(v, last+1, right, reverse, comp);
72 | }
73 |
74 | void swap(void *v[], int i, int j)
75 | {
76 | void *temp;
77 | temp = v[i];
78 | v[i] = v[j];
79 | v[j] = temp;
80 | }
81 |
82 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/4.getfloat.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define SIZE 10
5 |
6 | int getch(void);
7 | void ungetch(int);
8 |
9 | // compile with getch.c
10 | int main()
11 | {
12 | int n;
13 | double array[SIZE], getfloat(double *);
14 |
15 | for (n = 0; n < SIZE; n++)
16 | array[n] = 0.0;
17 |
18 | for (n = 0; n < SIZE && getfloat(&array[n]) != EOF; n++)
19 | ;
20 |
21 | for (n = 0; n < SIZE; n++)
22 | printf("%g ", array[n]);
23 |
24 | printf("\n");
25 | return 0;
26 | }
27 |
28 | double getfloat(double *pn)
29 | {
30 | int c, sign;
31 | double power;
32 |
33 | while (isspace(c = getch()))
34 | ;
35 |
36 | if (!isdigit(c) && c != EOF && c != '+' && c != '-' && c != '.') {
37 | ungetch(c);
38 | return 0.0;
39 | }
40 | sign = (c == '-') ? -1 : 1;
41 | if (c == '+' || c == '-') {
42 | c = getch();
43 | if (!isdigit(c) && c != '.') {
44 | ungetch(sign == 1 ? '+' : '-');
45 | return 0.0;
46 | }
47 | }
48 | for (*pn = 0.0; isdigit(c); c = getch())
49 | *pn = 10.0 * *pn + (c - '0');
50 |
51 | if (c == '.') {
52 | c = getch();
53 | }
54 |
55 | for (power = 1.0; isdigit(c); c = getch()) {
56 | *pn = 10.0 * *pn + (c - '0');
57 | power *= 10.0;
58 | }
59 |
60 | int eSign = 1;
61 | if (c == 'e' || c == 'E') {
62 | c = getch();
63 | if (c == '-') {
64 | eSign = -1;
65 | c = getch();
66 | } else if (c == '+') {
67 | c = getch();
68 | }
69 | }
70 |
71 | double ePower = 1.0;
72 | int eCount = 0;
73 | for (eCount = 0; isdigit(c); c = getch())
74 | eCount = 10.0 * eCount + (c - '0');
75 |
76 | while (eCount-- > 0)
77 | ePower *= 10;
78 |
79 | *pn = *pn / power * sign;
80 |
81 | if (eSign > 0)
82 | *pn *= ePower;
83 | else
84 | *pn /= ePower;
85 |
86 | if (c != EOF)
87 | ungetch(c);
88 | return c;
89 | }
90 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/40.sort-with-f.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define MAXLEN 10000
5 |
6 | #define MAXLINES 5000
7 | char *lineptr[MAXLINES];
8 |
9 | int readlines(char *lineptr[], int nlines);
10 | void writelines(char *lineptr[], int nlines);
11 |
12 | void qsort(void *lineptr[], int left, int right,
13 | int reverse, int foldcase, int (*comp)(void *, void *));
14 |
15 | int numcmp(const char *, const char *);
16 |
17 | void strtolower(const char *src, char *dst);
18 |
19 | // gcc 40.sort-with-f.c numcmp.c readlines-writelines.c 6.alloc.c case-convert.c
20 | main(int argc, char *argv[])
21 | {
22 | char c;
23 | int nlines;
24 | int numeric = 0;
25 | int reverse = 0;
26 | int foldcase = 0;
27 |
28 | while (--argc > 0 && (*++argv)[0] == '-')
29 | while (c = *++argv[0])
30 | switch(c) {
31 | case 'n':
32 | numeric = 1;
33 | break;
34 | case 'r':
35 | reverse = 1;
36 | break;
37 | case 'f':
38 | foldcase = 1;
39 | break;
40 | default:
41 | printf("find illegal option %c\n", c);
42 | return 1;
43 | }
44 |
45 | if (argc != 0) {
46 | printf("Usage: sort -n -r\n");
47 | return 1;
48 | }
49 |
50 | if ((nlines = readlines(lineptr, MAXLINES)) >= 0) {
51 | qsort((void **) lineptr, 0, nlines-1, reverse, foldcase,
52 | (int (*)(void*, void*))(numeric ? numcmp : strcmp));
53 | writelines(lineptr, nlines);
54 | return 0;
55 | } else {
56 | printf("input too big to sort\n");
57 | return 1;
58 | }
59 | }
60 |
61 | void qsort(void *v[], int left, int right,
62 | int reverse, int foldcase, int (*comp)(void *, void *))
63 | {
64 | int i, last;
65 | void swap(void *v[], int, int);
66 | char s1[MAXLEN], s2[MAXLEN];
67 |
68 | if (left >= right)
69 | return;
70 | swap(v, left, (left + right)/2);
71 | last = left;
72 | for (i = left+1; i <= right; i++) {
73 | char *vi;
74 | char *vleft;
75 |
76 | if (foldcase) {
77 | strtolower(v[i], s1);
78 | vi = s1;
79 | strtolower(v[left], s2);
80 | vleft = s2;
81 | } else {
82 | vi = v[i];
83 | vleft = v[left];
84 | }
85 |
86 | if (reverse && ((*comp)(vi, vleft) > 0))
87 | swap(v, ++last, i);
88 | else if (!reverse && ((*comp)(vi, vleft) < 0))
89 | swap(v, ++last, i);
90 | }
91 | swap(v, left, last);
92 | qsort(v, left, last-1, reverse, foldcase, comp);
93 | qsort(v, last+1, right, reverse, foldcase, comp);
94 | }
95 |
96 | void swap(void *v[], int i, int j)
97 | {
98 | void *temp;
99 | temp = v[i];
100 | v[i] = v[j];
101 | v[j] = temp;
102 | }
103 |
104 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/41.sort-with-d.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define MAXLEN 10000
5 |
6 | #define MAXLINES 5000
7 | char *lineptr[MAXLINES];
8 |
9 | int readlines(char *lineptr[], int nlines);
10 | void writelines(char *lineptr[], int nlines);
11 |
12 | void swap(void *v[], int, int);
13 |
14 | void qsort(void *lineptr[], int left, int right,
15 | int reverse, int foldcase, int (*comp)(void *, void *));
16 |
17 | // because qsort is unstable, to test -d
18 | void bubblesort(void *lineptr[], int len, int (*comp)(void*, void*));
19 |
20 | int numcmp(const char *, const char *);
21 | int dircmp(const char *, const char *);
22 |
23 | void strtolower(const char *src, char *dst);
24 |
25 | // gcc 41.sort-with-d.c numcmp.c readlines-writelines.c 6.alloc.c case-convert.c
26 | main(int argc, char *argv[])
27 | {
28 | char c;
29 | int nlines;
30 | int numeric = 0;
31 | int reverse = 0;
32 | int foldcase = 0;
33 | int directory = 0;
34 |
35 | while (--argc > 0 && (*++argv)[0] == '-')
36 | while (c = *++argv[0])
37 | switch(c) {
38 | case 'n':
39 | numeric = 1;
40 | break;
41 | case 'r':
42 | reverse = 1;
43 | break;
44 | case 'f':
45 | foldcase = 1;
46 | break;
47 | case 'd':
48 | directory = 1;
49 | break;
50 | default:
51 | printf("find illegal option %c\n", c);
52 | return 1;
53 | }
54 |
55 | if (argc != 0) {
56 | printf("Usage: sort -n -r\n");
57 | return 1;
58 | }
59 |
60 | if (numeric && directory) {
61 | printf("Cannot use the -n and -d at the same\n");
62 | return 1;
63 | }
64 |
65 | if ((nlines = readlines(lineptr, MAXLINES)) >= 0) {
66 | int (*comp)(void*, void*) = (int (*)(void*, void*))(numeric ? numcmp : strcmp);
67 | if (directory)
68 | comp = (int (*)(void*, void*))dircmp;
69 |
70 | if (directory)
71 | bubblesort((void **) lineptr, nlines, comp);
72 | else
73 | qsort((void **) lineptr, 0, nlines-1, reverse, foldcase, comp);
74 |
75 | writelines(lineptr, nlines);
76 | return 0;
77 | } else {
78 | printf("input too big to sort\n");
79 | return 1;
80 | }
81 | }
82 |
83 | void qsort(void *v[], int left, int right,
84 | int reverse, int foldcase, int (*comp)(void *, void *))
85 | {
86 | int i, last;
87 | char s1[MAXLEN], s2[MAXLEN];
88 |
89 | if (left >= right)
90 | return;
91 | swap(v, left, (left + right)/2);
92 | last = left;
93 | for (i = left+1; i <= right; i++) {
94 | char *vi;
95 | char *vleft;
96 |
97 | if (foldcase) {
98 | strtolower(v[i], s1);
99 | vi = s1;
100 | strtolower(v[left], s2);
101 | vleft = s2;
102 | } else {
103 | vi = v[i];
104 | vleft = v[left];
105 | }
106 |
107 | if (reverse && ((*comp)(vi, vleft) > 0))
108 | swap(v, ++last, i);
109 | else if (!reverse && ((*comp)(vi, vleft) < 0))
110 | swap(v, ++last, i);
111 | }
112 | swap(v, left, last);
113 | qsort(v, left, last-1, reverse, foldcase, comp);
114 | qsort(v, last+1, right, reverse, foldcase, comp);
115 | }
116 |
117 | void bubblesort(void *v[], int len, int (*comp)(void*, void*))
118 | {
119 | int i, j;
120 |
121 | for (i = 0; i < len; i++)
122 | for (j = 0; j < len; j++) {
123 | if ((*comp)(v[i], v[j]) < 0)
124 | swap(v, i, j);
125 | }
126 | }
127 |
128 | void swap(void *v[], int i, int j)
129 | {
130 | void *temp;
131 | temp = v[i];
132 | v[i] = v[j];
133 | v[j] = temp;
134 | }
135 |
136 | int dircmp(const char *p1, const char *p2)
137 | {
138 | char isdircase(const char c);
139 |
140 | const unsigned char *s1 = (const unsigned char *) p1;
141 | const unsigned char *s2 = (const unsigned char *) p2;
142 | unsigned char c1, c2;
143 |
144 | do {
145 | c1 = (unsigned char) *s1++;
146 | c2 = (unsigned char) *s2++;
147 |
148 | // only compare letters, numbers, blanks
149 | if (!isdircase(c1) || !isdircase(c2))
150 | c2 = c1;
151 |
152 | if (c1 == '\0')
153 | return c1 - c2;
154 | } while (c1 == c2);
155 |
156 | return c1 - c2;
157 | }
158 |
159 | char isdircase(const char c)
160 | {
161 | return isalnum(c) || c == ' ';
162 | }
163 |
164 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/42.dcl.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 |
5 | #define MAXTOKEN 100
6 |
7 | enum { NAME, PARENS, BRACKETS };
8 |
9 | void dcl(void);
10 | void dirdcl(void);
11 |
12 | int gettoken(void);
13 | int tokentype; // type of last token
14 | char token[MAXTOKEN]; // last token string
15 | char name[MAXTOKEN]; // identifier name
16 | char datatype[MAXTOKEN]; // data type = char, int, etc.
17 | char out[1000]; // output string
18 |
19 | // gcc 42.dcl.c getch.c
20 | main()
21 | {
22 | while (gettoken() != EOF) { // 1st token on line
23 | strcpy(datatype, token);
24 | out[0] = '\0';
25 | dcl();
26 | if (tokentype != '\n')
27 | printf("syntax error\n");
28 | printf("%s: %s %s\n", name, out, datatype);
29 | }
30 |
31 | return 0;
32 | }
33 |
34 | void dcl(void)
35 | {
36 | int ns;
37 |
38 | for (ns = 0; gettoken() == '*';)
39 | ns++;
40 |
41 | dirdcl();
42 | while (ns-- > 0)
43 | strcat(out, " pointer to");
44 | }
45 |
46 | void dirdcl(void)
47 | {
48 | int type;
49 |
50 | if (tokentype == '(') {
51 | dcl();
52 |
53 | if (tokentype != ')')
54 | printf("error: missing )\n");
55 | } else if (tokentype == NAME)
56 | strcpy(name, token);
57 | else
58 | printf("error: expected name or (dcl)\n");
59 |
60 | while ((type = gettoken()) == PARENS || type == BRACKETS)
61 | if (type == PARENS)
62 | strcat(out, " function returning");
63 | else {
64 | strcat(out, " array");
65 | strcat(out, token);
66 | strcat(out, " of");
67 | }
68 | }
69 |
70 | int gettoken(void)
71 | {
72 | int c, getch(void);
73 | void ungetch(int);
74 | char *p = token;
75 |
76 | while ((c = getch()) == ' ' || c == '\t')
77 | ;
78 |
79 | if (c == '(') {
80 | if ((c = getch()) == ')') {
81 | strcpy(token, "()");
82 | return tokentype = PARENS;
83 | } else {
84 | ungetch(c);
85 | return tokentype = '(';
86 | }
87 | } else if (c == '[') {
88 | for (*p++ = c; (*p++ = getch()) != ']'; )
89 | ;
90 | *p = '\0';
91 | return tokentype = BRACKETS;
92 | } else if (isalpha(c)) {
93 | for (*p++ = c; isalnum(c = getch()); )
94 | *p++ = c;
95 | *p = '\0';
96 | ungetch(c);
97 | return tokentype = NAME;
98 | } else {
99 | return tokentype = c;
100 | }
101 | }
102 |
103 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/43.dcl-error-handle.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 |
5 | #define MAXTOKEN 100
6 |
7 | #define DATATYPE_LEN 6
8 |
9 | enum { NAME, PARENS, BRACKETS };
10 |
11 | void dcl(void);
12 | void dirdcl(void);
13 |
14 | int isvalid_datatype(const char*);
15 |
16 | int gettoken(void);
17 | int tokentype; // type of last token
18 | char token[MAXTOKEN]; // last token string
19 | char name[MAXTOKEN]; // identifier name
20 | char datatype[MAXTOKEN]; // data type = char, int, etc.
21 | char out[1000]; // output string
22 |
23 | // gcc 43.dcl-error-handle.c getch.c
24 | main()
25 | {
26 | while (gettoken() != EOF) { // 1st token on line
27 | strcpy(datatype, token);
28 |
29 | if (tokentype != NAME) {
30 | printf("%c is not a valid datatype\n", tokentype);
31 | continue;
32 | } else if (!isvalid_datatype(datatype)) {
33 | printf("%s is not a valid datatype\n", datatype);
34 | continue;
35 | }
36 |
37 | out[0] = '\0';
38 | dcl();
39 | if (tokentype != '\n')
40 | printf("syntax error\n");
41 | printf("%s: %s %s\n", name, out, datatype);
42 | }
43 |
44 | return 0;
45 | }
46 |
47 | void dcl(void)
48 | {
49 | int ns;
50 |
51 | for (ns = 0; gettoken() == '*';)
52 | ns++;
53 |
54 | dirdcl();
55 | while (ns-- > 0)
56 | strcat(out, " pointer to");
57 | }
58 |
59 | void dirdcl(void)
60 | {
61 | int type;
62 |
63 | if (tokentype == '(') {
64 | dcl();
65 |
66 | if (tokentype != ')')
67 | printf("error: missing )\n");
68 | } else if (tokentype == NAME)
69 | strcpy(name, token);
70 | else
71 | printf("error: expected name or (dcl)\n");
72 |
73 | while ((type = gettoken()) == PARENS || type == BRACKETS)
74 | if (type == PARENS)
75 | strcat(out, " function returning");
76 | else {
77 | strcat(out, " array");
78 | strcat(out, token);
79 | strcat(out, " of");
80 | }
81 | }
82 |
83 | int gettoken(void)
84 | {
85 | int c, getch(void);
86 | void ungetch(int);
87 | char *p = token;
88 |
89 | while ((c = getch()) == ' ' || c == '\t')
90 | ;
91 |
92 | if (c == '(') {
93 | if ((c = getch()) == ')') {
94 | strcpy(token, "()");
95 | return tokentype = PARENS;
96 | } else {
97 | ungetch(c);
98 | return tokentype = '(';
99 | }
100 | } else if (c == '[') {
101 | for (*p++ = c; (*p++ = getch()) != ']'; )
102 | ;
103 | *p = '\0';
104 | return tokentype = BRACKETS;
105 | } else if (isalpha(c)) {
106 | for (*p++ = c; isalnum(c = getch()); )
107 | *p++ = c;
108 | *p = '\0';
109 | ungetch(c);
110 | return tokentype = NAME;
111 | } else {
112 | return tokentype = c;
113 | }
114 | }
115 |
116 | int isvalid_datatype(const char* s)
117 | {
118 | char *datatypes[DATATYPE_LEN] = { "char", "short", "int", "long", "float", "double" };
119 |
120 | int len = 0;
121 | while (len < DATATYPE_LEN)
122 | if (strcmp(s, datatypes[len++]) == 0)
123 | return 1;
124 |
125 | return 0;
126 | }
127 |
128 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/44.undcl.c:
--------------------------------------------------------------------------------
1 | /*
2 | * Exercise 5-19. Modify undcl so that it does not add redundant parentheses to declarations.
3 | * undcl: convert word description to declaration
4 | *
5 | * e.g.
6 | * x * int -> int *x
7 | * argv * * char -> char **argv
8 | * daytab * [] int -> int (*daytab)[]
9 | * daytab [] * int -> int *daytab[]
10 | * comp () * void -> void *comp()
11 | * comp * () void -> void (*comp)()
12 | * x () * [] * () char -> char (*(*x())[])()
13 | * x [] * () * [] char -> char (*(*x[])())[]
14 | */
15 |
16 | #include
17 | #include
18 |
19 | #define MAXTOKEN 100
20 |
21 | enum { NAME, PARENS, BRACKETS };
22 |
23 | int gettoken(void);
24 | int tokentype; // type of last token
25 | char token[MAXTOKEN]; // last token string
26 | char out[1000]; // output string
27 |
28 | // gcc 44.undcl.c getch.c
29 | // cat 44.undcl.test | ./a.out
30 | main()
31 | {
32 | int type;
33 | char temp[MAXTOKEN];
34 |
35 | while (gettoken() != EOF) {
36 | strcpy(out, token);
37 | while ((type = gettoken()) != '\n') {
38 | if (type == PARENS) {
39 | if (out[0] == '*') {
40 | sprintf(temp, "(%s)", out);
41 | strcpy(out, temp);
42 | }
43 | strcat(out, token);
44 | } else if (type == BRACKETS) {
45 | if (out[0] == '*' || strstr(out, "()") != NULL) {
46 | sprintf(temp, "(%s)", out);
47 | strcpy(out, temp);
48 | }
49 | strcat(out, token);
50 | } else if (type == '*') {
51 | sprintf(temp, "*%s", out);
52 | strcpy(out, temp);
53 | } else if (type == NAME) {
54 | sprintf(temp, "%s %s", token, out);
55 | strcpy(out, temp);
56 | } else
57 | printf("invalid input at %s\n", token);
58 | }
59 |
60 | printf("%s\n", out);
61 | }
62 | return 0;
63 | }
64 |
65 |
66 | int gettoken(void)
67 | {
68 | int c, getch(void);
69 | void ungetch(int);
70 | char *p = token;
71 |
72 | while ((c = getch()) == ' ' || c == '\t')
73 | ;
74 |
75 | if (c == '(') {
76 | if ((c = getch()) == ')') {
77 | strcpy(token, "()");
78 | return tokentype = PARENS;
79 | } else {
80 | ungetch(c);
81 | return tokentype = '(';
82 | }
83 | } else if (c == '[') {
84 | for (*p++ = c; (*p++ = getch()) != ']'; )
85 | ;
86 | *p = '\0';
87 | return tokentype = BRACKETS;
88 | } else if (isalpha(c)) {
89 | for (*p++ = c; isalnum(c = getch()); )
90 | *p++ = c;
91 | *p = '\0';
92 | ungetch(c);
93 | return tokentype = NAME;
94 | } else {
95 | return tokentype = c;
96 | }
97 | }
98 |
99 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/44.undcl.test:
--------------------------------------------------------------------------------
1 | x * int
2 | argv * * char
3 | daytab * [] int
4 | daytab [] * int
5 | comp () * void
6 | comp * () void
7 | x () * [] * () char
8 | x [] * () * [] char
9 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/5.strlen-pointer.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int main()
4 | {
5 | int strlen(char*);
6 |
7 | char array[100];
8 | char *ptr = "Hello";
9 |
10 | int l = strlen("hello, world");
11 | printf("%d\n", l);
12 |
13 | l = strlen(array);
14 | printf("%d\n", l);
15 |
16 | l = strlen(ptr);
17 | printf("%d\n", l);
18 | }
19 |
20 | int strlen(char *s)
21 | {
22 | int n;
23 |
24 | for (n = 0; *s != '\0'; s++)
25 | n++;
26 |
27 | return n;
28 | }
29 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/6.alloc.c:
--------------------------------------------------------------------------------
1 | #define ALLOCSIZE 1000000
2 |
3 | static char allocbuf[ALLOCSIZE];
4 | static char *allocp = allocbuf;
5 |
6 | char *alloc(int n)
7 | {
8 | if (allocbuf + ALLOCSIZE - allocp >= n) {
9 | allocp += n;
10 | return allocp - n;
11 | } else
12 | return 0;
13 | }
14 |
15 | void afree(char *p)
16 | {
17 | if (p >= allocbuf && p < allocbuf + ALLOCSIZE)
18 | allocp = p;
19 | }
20 |
21 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/7.alloc.test.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | int main()
5 | {
6 | char *alloc(int);
7 | void afree(char*);
8 |
9 | char *p = alloc(10);
10 | if (NULL == p)
11 | return -1;
12 |
13 | *p++ = 'H';
14 | *p++ = 'e';
15 | *p++ = 'l';
16 | *p++ = 'l';
17 | *p++ = 'o';
18 | *p++ = '\0';
19 | p -= 6;
20 |
21 | printf("%s\n", p);
22 |
23 | afree(p);
24 |
25 | printf("%s\n", p);
26 |
27 | p = alloc(10001);
28 |
29 | if (NULL == p)
30 | printf("overflow!\n");
31 |
32 | printf("%d\n", NULL);
33 |
34 | return 0;
35 | }
36 |
37 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/8.strlen-address-arithmetic.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int main()
4 | {
5 | int strlen(char*);
6 |
7 | char array[100];
8 | char *ptr = "Hello";
9 |
10 | int l = strlen("hello, world");
11 | printf("%d\n", l);
12 |
13 | l = strlen(array);
14 | printf("%d\n", l);
15 |
16 | l = strlen(ptr);
17 | printf("%d\n", l);
18 | }
19 |
20 | int strlen(char *s)
21 | {
22 | char *p = s;
23 |
24 | while (*p != '\0')
25 | p++;
26 |
27 | return p - s;
28 | }
29 |
30 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/9.strcpy-array-subscript.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int main()
4 | {
5 | void strcpyArray(char*, char*);
6 |
7 | char t[] = "Hello, World!";
8 | char s[100];
9 | strcpyArray(s, t);
10 | printf("%s\n", s);
11 |
12 | return 0;
13 | }
14 |
15 | void strcpyArray(char *s, char *t)
16 | {
17 | int i;
18 |
19 | i = 0;
20 | while ((s[i] = t[i]) != '\0')
21 | i++;
22 | }
23 |
24 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/case-convert.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | void strtolower(const char *src, char *dst)
4 | {
5 | while (*src) {
6 | *dst++ = tolower(*src++);
7 | }
8 | *dst = '\0';
9 | }
10 |
11 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/getch.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define BUFSIZE 100
5 |
6 | int buf[BUFSIZE];
7 | int bufp = 0;
8 |
9 | int value = EOF;
10 |
11 | int getch(void)
12 | {
13 | return (bufp > 0) ? buf[--bufp] : getchar();
14 | }
15 |
16 | void ungetch(int c)
17 | {
18 | if (bufp >= BUFSIZE)
19 | printf("ungetch: too many characters\n");
20 | else
21 | buf[bufp++] = c;
22 | }
23 |
24 | void ungetchs(char s[])
25 | {
26 | int len = strlen(s);
27 | while (len > 0) {
28 | ungetch(s[--len]);
29 | }
30 | }
31 |
32 | int getchOne(void)
33 | {
34 | if (value != EOF) {
35 | int temp = value;
36 | value = EOF;
37 | return temp;
38 | }
39 | else
40 | return getchar();
41 | }
42 |
43 | void ungetchOne(int c)
44 | {
45 | if (value != EOF)
46 | printf("ungetchOne: cannot ungetch more char\n");
47 | else
48 | value = c;
49 | }
50 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/mygetline.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 |
4 | int mygetline(char s[], int lim)
5 | {
6 | int c, i;
7 | i = 0;
8 | while (--lim > 0 && (c = getchar()) != EOF && c != '\n')
9 | s[i++] = c;
10 | if (c == '\n')
11 | s[i++] = c;
12 | s[i] = '\0';
13 | return i;
14 | }
15 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/numcmp.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | int numcmp(char *s1, char *s2)
4 | {
5 | double v1, v2;
6 |
7 | v1 = atof(s1);
8 | v2 = atof(s2);
9 | if (v1 < v2)
10 | return -1;
11 | else if (v1 > v2)
12 | return 1;
13 | else
14 | return 0;
15 | }
16 |
17 |
--------------------------------------------------------------------------------
/chapter-5-pointers-and-arrays/readlines-writelines.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define MAXLEN 10000
5 |
6 | int readlines(char *lineptr[], int maxlines)
7 | {
8 | int mygetline(char *, int);
9 | char *alloc(int);
10 |
11 | int len, nlines;
12 | char *p, line[MAXLEN];
13 | nlines = 0;
14 | while ((len = mygetline(line, MAXLEN)) > 0)
15 | if (nlines >= maxlines || (p = alloc(len)) == NULL)
16 | return -1;
17 | else {
18 | line[len-1] = '\0';
19 | strcpy(p, line);
20 | lineptr[nlines++] = p;
21 | }
22 |
23 | return nlines;
24 | }
25 |
26 | void writelines(char *lineptr[], int nlines)
27 | {
28 | while (nlines-- > 0)
29 | printf("%s\n", *lineptr++);
30 | }
31 |
32 | int mygetline(char *s, int lim)
33 | {
34 | int c;
35 | char *t = s;
36 | while (--lim > 0 && (c = getchar()) != EOF && c != '\n')
37 | *t++ = c;
38 |
39 | if (c == '\n')
40 | *t++ = c;
41 |
42 | *t = '\0';
43 | return t - s;
44 | }
45 |
46 |
--------------------------------------------------------------------------------
/chapter-6-structures/1.structures-and-functions.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | #define XMAX 100
4 | #define YMAX 100
5 |
6 | #define min(a, b) ((a) < (b) ? (a) : (b))
7 | #define max(a, b) ((a) > (b) ? (a) : (b))
8 |
9 | struct point {
10 | int x;
11 | int y;
12 | };
13 |
14 | struct rect {
15 | struct point pt1;
16 | struct point pt2;
17 | };
18 |
19 | main()
20 | {
21 | struct rect screen;
22 | struct point middle;
23 | struct point makepoint(int, int);
24 | struct point addpoint(struct point, struct point);
25 | int ptinrect(struct point, struct rect);
26 | struct rect canonrect(struct rect);
27 |
28 | screen.pt1 = makepoint(0, 0);
29 | screen.pt2 = makepoint(XMAX, YMAX);
30 | middle = makepoint((screen.pt1.x + screen.pt2.x) / 2,
31 | (screen.pt1.y + screen.pt2.y) /2);
32 |
33 | printf("middle.x: %d, middle.y: %d\n", middle.x, middle.y);
34 |
35 | struct point p1 = { 5, 5 };
36 |
37 | p1 = addpoint(p1, middle);
38 |
39 | printf("p1.x: %d, p1.y: %d\n", p1.x, p1.y);
40 |
41 | int p1inscreen = ptinrect(p1, screen);
42 |
43 | printf("p1inscreen: %d\n", p1inscreen);
44 |
45 | struct point p2;
46 |
47 | printf("p2.x: %d, p2.y: %d\n", p2.x, p2.y);
48 |
49 |
50 | struct rect r1 = { 10, 10, 0, 0 };
51 |
52 | printf("r1.pt1.x: %d, r1.pt1.y: %d, r1.pt2.x: %d, r1.pt2.y: %d\n",
53 | r1.pt1.x, r1.pt1.y, r1.pt2.x, r1.pt2.y);
54 |
55 | r1 = canonrect(r1);
56 |
57 | printf("r1.pt1.x: %d, r1.pt1.y: %d, r1.pt2.x: %d, r1.pt2.y: %d\n",
58 | r1.pt1.x, r1.pt1.y, r1.pt2.x, r1.pt2.y);
59 |
60 | struct rect r2 = { { 20, 0 }, { 0, 20 } };
61 |
62 | printf("r2.pt1.x: %d, r2.pt1.y: %d, r2.pt2.x: %d, r2.pt2.y: %d\n",
63 | r2.pt1.x, r2.pt1.y, r2.pt2.x, r2.pt2.y);
64 |
65 | r2 = canonrect(r2);
66 |
67 | printf("r2.pt1.x: %d, r2.pt1.y: %d, r2.pt2.x: %d, r2.pt2.y: %d\n",
68 | r2.pt1.x, r2.pt1.y, r2.pt2.x, r2.pt2.y);
69 |
70 |
71 | struct point origin = { 15, 20 };
72 | struct point *pp;
73 |
74 | pp = &origin;
75 | printf("origin is (%d, %d)\n", (*pp).x, (*pp).y);
76 | printf("origin is (%d, %d)\n", pp->x, pp->y);
77 |
78 | return 0;
79 | }
80 |
81 | struct point makepoint(int x, int y)
82 | {
83 | struct point temp;
84 |
85 | temp.x = x;
86 | temp.y = y;
87 | return temp;
88 | }
89 |
90 | struct point addpoint(struct point p1, struct point p2)
91 | {
92 | p1.x += p2.x;
93 | p1.y += p2.y;
94 | return p1;
95 | }
96 |
97 | int ptinrect(struct point p, struct rect r)
98 | {
99 | return p.x >= r.pt1.x && p.x < r.pt2.x
100 | && p.y >= r.pt1.y && p.y < r.pt2.y;
101 | }
102 |
103 | struct rect canonrect(struct rect r)
104 | {
105 | struct rect temp;
106 |
107 | temp.pt1.x = min(r.pt1.x, r.pt2.x);
108 | temp.pt1.y = min(r.pt1.y, r.pt2.y);
109 | temp.pt2.x = max(r.pt1.x, r.pt2.x);
110 | temp.pt2.y = max(r.pt1.y, r.pt2.y);
111 | return temp;
112 | }
113 |
114 |
--------------------------------------------------------------------------------
/chapter-6-structures/2.keywords-count.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 |
5 | #define MAXWORD 100
6 |
7 | struct key {
8 | char *word;
9 | int count;
10 | } keytab[] = {
11 | { "auto", 0 }, { "break", 0 }, { "case", 0 }, { "char", 0 },
12 | { "const", 0 }, { "continue", 0 }, { "default", 0 }, { "double", 0 }, { "else", 0 },
13 | { "enum", 0 }, { "extern", 0 }, { "float", 0 }, { "for", 0 },
14 | { "goto", 0 }, { "if", 0 }, { "int", 0 }, { "long", 0 },
15 | { "register", 0 }, { "return", 0 }, { "short", 0 }, { "signed", 0 },
16 | { "sizeof", 0 }, { "static", 0 }, { "struct", 0 }, { "switch", 0 },
17 | { "typedef", 0 }, { "union", 0 }, { "unsigned", 0 }, { "void", 0 },
18 | { "volatile", 0 }, { "while", 0 }
19 | };
20 |
21 | #define NKEYS (sizeof keytab / sizeof keytab[0])
22 |
23 | int getword(char *, int);
24 | int binsearch(char *, struct key *, int);
25 |
26 | // gcc 2.keyowrds-count.c getch.c
27 | main()
28 | {
29 | int n;
30 | char word[MAXWORD];
31 |
32 | while (getword(word, MAXWORD) != EOF)
33 | if (isalpha(word[0]))
34 | if ((n = binsearch(word, keytab, NKEYS)) >= 0)
35 | keytab[n].count++;
36 |
37 | for (n = 0; n < NKEYS; n++)
38 | if (keytab[n].count > 0)
39 | printf("%4d %s\n",
40 | keytab[n].count, keytab[n].word);
41 |
42 | return 0;
43 | }
44 |
45 | int binsearch(char *word, struct key tab[], int n)
46 | {
47 | int cond;
48 | int low, high, mid;
49 |
50 | low = 0;
51 | high = n - 1;
52 | while (low <= high) {
53 | mid = (low+high) / 2;
54 | if ((cond = strcmp(word, tab[mid].word)) < 0)
55 | high = mid - 1;
56 | else if (cond > 0)
57 | low = mid + 1;
58 | else
59 | return mid;
60 | }
61 | return -1;
62 | }
63 |
64 | int getword(char *word, int lim)
65 | {
66 | int c, getch(void);
67 | void ungetch(int);
68 | char *w = word;
69 |
70 | while (isspace(c = getch()))
71 | ;
72 | if (c != EOF)
73 | *w++ = c;
74 | if (!isalpha(c)) {
75 | *w = '\0';
76 | return c;
77 | }
78 | for ( ; --lim > 0; w++)
79 | if (!isalnum(*w = getch())) {
80 | ungetch(*w);
81 | break;
82 | }
83 | *w = '\0';
84 | return word[0];
85 | }
86 |
87 |
--------------------------------------------------------------------------------
/chapter-6-structures/3.getword.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 |
5 | #define MAXWORD 100
6 |
7 | struct key {
8 | char *word;
9 | int count;
10 | } keytab[] = {
11 | { "auto", 0 }, { "break", 0 }, { "case", 0 }, { "char", 0 },
12 | { "const", 0 }, { "continue", 0 }, { "default", 0 }, { "double", 0 }, { "else", 0 },
13 | { "enum", 0 }, { "extern", 0 }, { "float", 0 }, { "for", 0 },
14 | { "goto", 0 }, { "if", 0 }, { "int", 0 }, { "long", 0 },
15 | { "register", 0 }, { "return", 0 }, { "short", 0 }, { "signed", 0 },
16 | { "sizeof", 0 }, { "static", 0 }, { "struct", 0 }, { "switch", 0 },
17 | { "typedef", 0 }, { "union", 0 }, { "unsigned", 0 }, { "void", 0 },
18 | { "volatile", 0 }, { "while", 0 }
19 | };
20 |
21 | #define NKEYS (sizeof keytab / sizeof keytab[0])
22 |
23 | int getword(char *, int);
24 | int binsearch(char *, struct key *, int);
25 |
26 | // gcc 3.getword.c getch.c
27 | main()
28 | {
29 | int n;
30 | char word[MAXWORD];
31 |
32 | while (getword(word, MAXWORD) != EOF) {
33 | if (isalpha(word[0]))
34 | if ((n = binsearch(word, keytab, NKEYS)) >= 0)
35 | keytab[n].count++;
36 | }
37 |
38 | for (n = 0; n < NKEYS; n++)
39 | if (keytab[n].count > 0)
40 | printf("%4d %s\n",
41 | keytab[n].count, keytab[n].word);
42 |
43 | return 0;
44 | }
45 |
46 | int binsearch(char *word, struct key tab[], int n)
47 | {
48 | int cond;
49 | int low, high, mid;
50 |
51 | low = 0;
52 | high = n - 1;
53 | while (low <= high) {
54 | mid = (low+high) / 2;
55 | if ((cond = strcmp(word, tab[mid].word)) < 0)
56 | high = mid - 1;
57 | else if (cond > 0)
58 | low = mid + 1;
59 | else
60 | return mid;
61 | }
62 | return -1;
63 | }
64 |
65 | int getword(char *word, int lim)
66 | {
67 | int c, getch(void);
68 | void ungetch(int);
69 | char *w = word;
70 |
71 | while (isspace(c = getch()))
72 | ;
73 | if (c != EOF)
74 | *w++ = c;
75 |
76 | if (c == '/') {
77 | *w = getch();
78 | if (*w == '/') {
79 | for ( ; --lim > 0; w++) {
80 | if ((*w = getch()) == '\n') {
81 | *++w = '\0';
82 | return c;
83 | }
84 | }
85 | } else if (*w == '*') {
86 | for ( ; --lim > 0; w++) {
87 | if ((*w = getch()) == '*') {
88 | if ((*++w = getch()) == '/') {
89 | *++w = '\0';
90 | return c;
91 | }
92 | }
93 | }
94 | } else {
95 | ungetch(*w);
96 | }
97 | }
98 |
99 | if (c == '\'') {
100 | *w++ = getch();
101 | *w++ = getch();
102 | *w = '\0';
103 | return c;
104 | }
105 |
106 | if (c == '"')
107 | for ( ; --lim > 0; w++)
108 | if ((*w = getch()) == '"') {
109 | *++w = '\0';
110 | return c;
111 | }
112 |
113 | if (!isalpha(c) && c != '_') {
114 | *w = '\0';
115 | return c;
116 | }
117 | for ( ; --lim > 0; w++)
118 | if (!isalnum(*w = getch()) && *w != '_') {
119 | ungetch(*w);
120 | break;
121 | }
122 | *w = '\0';
123 | return word[0];
124 | }
125 |
126 | // for test sizeof return int double register
127 |
128 | /* sizeof struct void while break
129 | */
130 |
131 |
--------------------------------------------------------------------------------
/chapter-6-structures/4.keywords-count-pointer.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 |
5 | #define MAXWORD 100
6 |
7 | struct key {
8 | char *word;
9 | int count;
10 | } keytab[] = {
11 | { "auto", 0 }, { "break", 0 }, { "case", 0 }, { "char", 0 },
12 | { "enum", 0 }, { "extern", 0 }, { "float", 0 }, { "for", 0 },
13 | { "goto", 0 }, { "if", 0 }, { "int", 0 }, { "long", 0 },
14 | { "register", 0 }, { "return", 0 }, { "short", 0 }, { "signed", 0 },
15 | { "const", 0 }, { "continue", 0 }, { "default", 0 }, { "double", 0 },
16 | { "else", 0 }, { "sizeof", 0 }, { "static", 0 }, { "struct", 0 },
17 | { "switch", 0 }, { "typedef", 0 }, { "union", 0 }, { "unsigned", 0 },
18 | { "void", 0 }, { "volatile", 0 }, { "while", 0 }
19 | };
20 |
21 | #define NKEYS (sizeof keytab / sizeof keytab[0])
22 |
23 | int getword(char *, int);
24 | struct key *binsearch(char *, struct key *, int);
25 | void qsort(struct key v[], int, int);
26 |
27 | // gcc 4.keyowrds-count-pointer.c getch.c
28 | main()
29 | {
30 | char word[MAXWORD];
31 | struct key *p;
32 |
33 | qsort(keytab, 0, NKEYS-1);
34 |
35 | while (getword(word, MAXWORD) != EOF)
36 | if (isalpha(word[0]))
37 | if ((p = binsearch(word, keytab, NKEYS)) != NULL)
38 | p->count++;
39 |
40 | for (p = keytab; p < keytab + NKEYS; p++)
41 | if (p->count > 0)
42 | printf("%4d %s\n", p->count, p->word);
43 |
44 | return 0;
45 | }
46 |
47 | struct key *binsearch(char *word, struct key *tab, int n)
48 | {
49 | int cond;
50 | struct key *low = &tab[0];
51 | struct key *high = &tab[n];
52 | struct key *mid;
53 |
54 | while (low < high) {
55 | mid = low + (high-low) / 2;
56 | if ((cond = strcmp(word, mid->word)) < 0)
57 | high = mid;
58 | else if (cond > 0)
59 | low = mid + 1;
60 | else
61 | return mid;
62 | }
63 | return NULL;
64 | }
65 |
66 | int getword(char *word, int lim)
67 | {
68 | int c, getch(void);
69 | void ungetch(int);
70 | char *w = word;
71 |
72 | while (isspace(c = getch()))
73 | ;
74 | if (c != EOF)
75 | *w++ = c;
76 | if (!isalpha(c)) {
77 | *w = '\0';
78 | return c;
79 | }
80 | for ( ; --lim > 0; w++)
81 | if (!isalnum(*w = getch())) {
82 | ungetch(*w);
83 | break;
84 | }
85 | *w = '\0';
86 | return word[0];
87 | }
88 |
89 | void qsort(struct key v[], int left, int right)
90 | {
91 | int i, last;
92 | void swap(struct key v[], int i, int j);
93 |
94 | if (left >= right)
95 | return;
96 | swap(v, left, (left + right) / 2);
97 | last = left;
98 | for (i = left+1; i <= right; i++)
99 | if (strcmp(v[i].word, v[left].word) < 0)
100 | swap(v, ++last, i);
101 | swap(v, left, last);
102 | qsort(v, left, last-1);
103 | qsort(v, last+1, right);
104 | }
105 |
106 | void swap(struct key v[], int i, int j)
107 | {
108 | struct key temp;
109 |
110 | temp = v[i];
111 | v[i] = v[j];
112 | v[j] = temp;
113 | }
114 |
115 |
--------------------------------------------------------------------------------
/chapter-6-structures/5.words-count-binary-tree.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 | #include
5 |
6 | #define MAXWORD 100
7 |
8 | struct tnode {
9 | char *word;
10 | int count;
11 | struct tnode *left;
12 | struct tnode *right;
13 | };
14 |
15 | struct tnode *addtree(struct tnode *, char *);
16 | void treeprint(struct tnode *);
17 | int getword(char *, int);
18 |
19 | // gcc 5.words-count-binary-tree.c getch.c
20 | main()
21 | {
22 | struct tnode *root;
23 | char word[MAXWORD];
24 |
25 | root = NULL;
26 | while (getword(word, MAXWORD) != EOF)
27 | if (isalpha(word[0]))
28 | root = addtree(root, word);
29 | treeprint(root);
30 |
31 | return 0;
32 | }
33 |
34 | int getword(char *word, int lim)
35 | {
36 | int c, getch(void);
37 | void ungetch(int);
38 | char *w = word;
39 |
40 | while (isspace(c = getch()))
41 | ;
42 | if (c != EOF)
43 | *w++ = c;
44 | if (!isalpha(c)) {
45 | *w = '\0';
46 | return c;
47 | }
48 | for ( ; --lim > 0; w++)
49 | if (!isalnum(*w = getch())) {
50 | ungetch(*w);
51 | break;
52 | }
53 | *w = '\0';
54 | return word[0];
55 | }
56 |
57 | struct tnode *talloc(void);
58 | char *mystrdup(char *s);
59 |
60 | struct tnode *addtree(struct tnode *p, char *w)
61 | {
62 | int cond;
63 |
64 | if (p == NULL) {
65 | p = talloc();
66 | p->word = mystrdup(w);
67 | p->count = 1;
68 | p->left = p-> right = NULL;
69 | } else if ((cond = strcmp(w, p->word)) == 0)
70 | p->count++;
71 | else if (cond < 0)
72 | p->left = addtree(p->left, w);
73 | else
74 | p->right = addtree(p->right, w);
75 | return p;
76 | }
77 |
78 | void treeprint(struct tnode *p)
79 | {
80 | if (p != NULL) {
81 | treeprint(p->left);
82 | printf("%4d %s\n", p->count, p->word);
83 | treeprint(p->right);
84 | }
85 | }
86 |
87 | struct tnode *talloc(void)
88 | {
89 | return (struct tnode *) malloc(sizeof(struct tnode));
90 | }
91 |
92 | char *mystrdup(char *s)
93 | {
94 | char *p;
95 |
96 | p = (char *) malloc(strlen(s)+1);
97 | if (p != NULL)
98 | strcpy(p, s);
99 |
100 | return p;
101 | }
102 |
103 |
--------------------------------------------------------------------------------
/chapter-6-structures/6.variables-group.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 | #include
5 |
6 | #define MAXWORD 100
7 |
8 | struct tnode {
9 | char *word;
10 | int count;
11 | struct tnode *left;
12 | struct tnode *right;
13 | };
14 |
15 | struct list {
16 | struct tnode *cur;
17 | struct list *next;
18 | };
19 |
20 | const char *keywords[] = {"char", "double", "int", "float", "void"};
21 |
22 | struct tnode *addtree(struct tnode *, char *);
23 | void treeprint(struct tnode *);
24 | int getword(char *, int);
25 | int iskeyword(char *word);
26 | int binsearch(char *word, const char *keywords[], int n);
27 | int getvariable(char *word, int lim);
28 | void addgroup(struct list *, char *, int same_char);
29 | void sort_groups(struct list *tlist, int same_char);
30 | void swap_tree_cur(struct list *pre, struct list *next);
31 | void groupprint(struct list *tlist);
32 |
33 | // gcc 6.variables-group.c getch.c
34 | main(int argc, char *argv[])
35 | {
36 | int same_char = 1;
37 | if (argc > 1)
38 | same_char = atoi(argv[1]);
39 |
40 | struct list *tlist = malloc(sizeof(struct list));
41 | tlist->cur = NULL;
42 | tlist->next = NULL;
43 |
44 | struct tnode *root;
45 | char word[MAXWORD];
46 |
47 | root = NULL;
48 | while (getword(word, MAXWORD) != EOF)
49 | if (iskeyword(word)) {
50 | getvariable(word, MAXWORD);
51 | if (isalpha(word[0])) {
52 | addgroup(tlist, word, same_char);
53 | }
54 | }
55 | sort_groups(tlist, same_char);
56 | groupprint(tlist);
57 |
58 | return 0;
59 | }
60 |
61 | int getword(char *word, int lim)
62 | {
63 | int c, getch(void);
64 | void ungetch(int);
65 | char *w = word;
66 |
67 | while (isspace(c = getch()))
68 | ;
69 | if (c != EOF)
70 | *w++ = c;
71 | if (!isalpha(c)) {
72 | *w = '\0';
73 | return c;
74 | }
75 | for ( ; --lim > 0; w++)
76 | if (!isalnum(*w = getch())) {
77 | ungetch(*w);
78 | break;
79 | }
80 | *w = '\0';
81 | return word[0];
82 | }
83 |
84 | int iskeyword(char *word)
85 | {
86 | if (binsearch(word, keywords, sizeof(keywords) / sizeof(keywords[0])) != -1)
87 | return 1;
88 | else
89 | return 0;
90 | }
91 |
92 | int binsearch(char *word, const char *keywords[], int n)
93 | {
94 | int cond;
95 | int low, high, mid;
96 |
97 | low = 0;
98 | high = n - 1;
99 | while (low <= high) {
100 | mid = (low+high) / 2;
101 | if ((cond = strcmp(word, keywords[mid])) < 0)
102 | high = mid - 1;
103 | else if (cond > 0)
104 | low = mid + 1;
105 | else
106 | return mid;
107 | }
108 | return -1;
109 | }
110 |
111 | int getvariable(char *word, int lim)
112 | {
113 | int c, getch(void);
114 | void ungetch(int);
115 | char *w = word;
116 |
117 | while (isspace(c = getch()) || c == '*')
118 | ;
119 | if (c != EOF)
120 | *w++ = c;
121 | if (!isalpha(c)) {
122 | *w = '\0';
123 | return c;
124 | }
125 | for ( ; --lim > 0; w++)
126 | if (!isalnum(*w = getch())) {
127 | ungetch(*w);
128 | break;
129 | }
130 | *w = '\0';
131 | return word[0];
132 | }
133 |
134 | struct tnode *talloc(void);
135 | char *mystrdup(char *s);
136 |
137 | void addgroup(struct list *tlist, char *word, int same_char)
138 | {
139 | if (tlist->cur == NULL) {
140 | tlist->cur = talloc();
141 | tlist->cur->word = mystrdup(word);
142 | tlist->cur->count = 1;
143 | tlist->cur->left = tlist->cur->right = NULL;
144 | } else {
145 | struct list *p = tlist, *pre = tlist;
146 | while (p != NULL && p->cur != NULL && strncmp(word, p->cur->word, same_char) != 0) {
147 | pre = p;
148 | p = p->next;
149 | }
150 | if (p == NULL) {
151 | p = malloc(sizeof(struct list));
152 | p->cur = NULL;
153 | p->next = NULL;
154 | addgroup(p, word, same_char);
155 | pre->next = p;
156 | } else {
157 | addtree(p->cur, word);
158 | }
159 | }
160 | }
161 |
162 | struct tnode *addtree(struct tnode *p, char *w)
163 | {
164 | int cond;
165 |
166 | if (p == NULL) {
167 | p = talloc();
168 | p->word = mystrdup(w); p->count = 1;
169 | p->left = p-> right = NULL;
170 | } else if ((cond = strcmp(w, p->word)) == 0)
171 | p->count++;
172 | else if (cond < 0)
173 | p->left = addtree(p->left, w);
174 | else
175 | p->right = addtree(p->right, w);
176 | return p;
177 | }
178 |
179 | void treeprint(struct tnode *p)
180 | {
181 | if (p != NULL) {
182 | treeprint(p->left);
183 | printf("%4d %s\n", p->count, p->word);
184 | treeprint(p->right);
185 | }
186 | }
187 |
188 | struct tnode *talloc(void)
189 | {
190 | return (struct tnode *) malloc(sizeof(struct tnode));
191 | }
192 |
193 | char *mystrdup(char *s)
194 | {
195 | char *p;
196 |
197 | p = (char *) malloc(strlen(s)+1);
198 | if (p != NULL)
199 | strcpy(p, s);
200 |
201 | return p;
202 | }
203 |
204 | void sort_groups(struct list *tlist, int same_char)
205 | {
206 | struct list *pre = tlist;
207 | struct list *p;
208 | int swapped = 0;
209 | while (pre != NULL) {
210 | p = pre;
211 | while (p != NULL && p->next != NULL) {
212 | if (strncmp(p->cur->word, p->next->cur->word, same_char) > 0) {
213 | swap_tree_cur(p, p->next);
214 | swapped = 1;
215 | }
216 | p = p->next;
217 | }
218 | if (swapped == 0)
219 | break;
220 | else
221 | swapped = 0;
222 | }
223 | }
224 |
225 | void swap_tree_cur(struct list *pre, struct list *next)
226 | {
227 | struct tnode *temp;
228 | temp = pre->cur;
229 | pre->cur = next->cur;
230 | next->cur = temp;
231 | }
232 |
233 | void groupprint(struct list *tlist)
234 | {
235 | int i = 0;
236 | struct list *p = tlist;
237 | while (p != NULL) {
238 | printf("Group %d:\n", i++);
239 | treeprint(p->cur);
240 | printf("\n");
241 | p = p->next;
242 | }
243 | }
244 |
245 |
--------------------------------------------------------------------------------
/chapter-6-structures/7.words-appear-lines.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 | #include
5 |
6 | #define MAXWORD 100
7 | #define MAX_LINES 100
8 |
9 | struct tnode {
10 | char *word;
11 | int count;
12 | int lines[MAX_LINES];
13 | struct tnode *left;
14 | struct tnode *right;
15 | };
16 |
17 | struct tnode *addtree(struct tnode *, char *);
18 | void treeprint(struct tnode *);
19 | int getword(char *, int);
20 |
21 | static int current_line = 1;
22 |
23 | // gcc 7.words-appear-lines.c getch.c
24 | main()
25 | {
26 | struct tnode *root;
27 | char word[MAXWORD];
28 |
29 | root = NULL;
30 | while (getword(word, MAXWORD) != EOF)
31 | if (isalpha(word[0]))
32 | root = addtree(root, word);
33 | treeprint(root);
34 |
35 | return 0;
36 | }
37 |
38 | int getword(char *word, int lim)
39 | {
40 | int c, getch(void);
41 | void ungetch(int);
42 | char *w = word;
43 |
44 | do {
45 | c = getch();
46 | if (c == '\n')
47 | ++current_line;
48 | } while (isspace(c));
49 |
50 | if (c != EOF)
51 | *w++ = c;
52 | if (!isalpha(c)) {
53 | *w = '\0';
54 | return c;
55 | }
56 | for ( ; --lim > 0; w++)
57 | if (!isalnum(*w = getch()) && *w != '_') {
58 | ungetch(*w);
59 | break;
60 | }
61 | *w = '\0';
62 | return word[0];
63 | }
64 |
65 | struct tnode *talloc(void);
66 | char *mystrdup(char *s);
67 |
68 | struct tnode *addtree(struct tnode *p, char *w)
69 | {
70 | int cond;
71 | int i;
72 |
73 | if (p == NULL) {
74 | p = talloc();
75 | p->word = mystrdup(w);
76 | p->count = 1;
77 | p->lines[0] = current_line;
78 | p->left = p-> right = NULL;
79 | } else if ((cond = strcmp(w, p->word)) == 0) {
80 | p->count++;
81 | i = 0;
82 | while (p->lines[i] != 0)
83 | ++i;
84 | //printf("i: %d\n", i);
85 | p->lines[i] = current_line;
86 | } else if (cond < 0)
87 | p->left = addtree(p->left, w);
88 | else
89 | p->right = addtree(p->right, w);
90 | return p;
91 | }
92 |
93 | void treeprint(struct tnode *p)
94 | {
95 | int i = 0;
96 | if (p != NULL) {
97 | treeprint(p->left);
98 | printf("%4d %s ", p->count, p->word);
99 | while (p->lines[i] != 0 && i < MAX_LINES)
100 | printf("%d ", p->lines[i++]);
101 | printf("\n");
102 | treeprint(p->right);
103 | }
104 | }
105 |
106 | struct tnode *talloc(void)
107 | {
108 | return (struct tnode *) malloc(sizeof(struct tnode));
109 | }
110 |
111 | char *mystrdup(char *s)
112 | {
113 | char *p;
114 |
115 | p = (char *) malloc(strlen(s)+1);
116 | if (p != NULL)
117 | strcpy(p, s);
118 |
119 | return p;
120 | }
121 |
122 |
--------------------------------------------------------------------------------
/chapter-6-structures/8.table-lookup.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 |
5 | struct nlist {
6 | struct nlist *next;
7 | char *name;
8 | char *defn;
9 | };
10 |
11 | #define HASHSIZE 101
12 |
13 | static struct nlist *hashtab[HASHSIZE];
14 |
15 | unsigned hash(char *s);
16 | struct nlist *lookup(char *s);
17 | struct nlist *install(char *name, char *defn);
18 | struct nlist *undef(char *name);
19 |
20 | int main()
21 | {
22 | install("name", "Trump");
23 | struct nlist *n = lookup("name");
24 | if (n != NULL)
25 | printf("n->defn: %s\n", n->defn);
26 | else
27 | printf("n == NULL\n");
28 |
29 | install("name", "Obama");
30 | lookup("test");
31 |
32 | n = lookup("name");
33 | printf("n->defn: %s\n", n->defn);
34 |
35 | n = undef("name");
36 | printf("n->defn: %s\n", n->defn);
37 | free(n->name);
38 | free(n->defn);
39 | free(n);
40 |
41 | n = lookup("name");
42 | printf("n == NULL: %d\n", n == NULL);
43 |
44 | return 0;
45 | }
46 |
47 | unsigned hash(char *s)
48 | {
49 | unsigned hashval;
50 | for (hashval = 0; *s != '\0'; ++s)
51 | hashval = *s + 31 * hashval;
52 | return hashval % HASHSIZE;
53 | }
54 |
55 | struct nlist *lookup(char *s)
56 | {
57 | struct nlist *np;
58 |
59 | for (np = hashtab[hash(s)]; np != NULL; np = np->next) {
60 | if (strcmp(s, np->name) == 0)
61 | return np;
62 | }
63 | return NULL;
64 | }
65 |
66 | struct nlist *install(char *name, char *defn)
67 | {
68 | struct nlist *np;
69 | unsigned hashval;
70 |
71 | if ((np = lookup(name)) == NULL) {
72 | np = (struct nlist *) malloc(sizeof(*np));
73 | if (np == NULL || (np->name = strdup(name)) == NULL)
74 | return NULL;
75 | hashval = hash(name);
76 | np->next = hashtab[hashval];
77 | hashtab[hashval] = np;
78 | } else
79 | free((void *) np->defn);
80 |
81 | if ((np->defn = strdup(defn)) == NULL)
82 | return NULL;
83 | return np;
84 | }
85 |
86 | struct nlist *undef(char *name)
87 | {
88 | struct nlist *np;
89 |
90 | if ((np = lookup(name)) == NULL)
91 | return NULL;
92 |
93 | unsigned hashval = hash(name);
94 | hashtab[hashval] = NULL;
95 |
96 | return np;
97 | }
98 |
99 |
--------------------------------------------------------------------------------
/chapter-6-structures/getch.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | #define BUFSIZE 100
5 |
6 | int buf[BUFSIZE];
7 | int bufp = 0;
8 |
9 | int value = EOF;
10 |
11 | int getch(void)
12 | {
13 | return (bufp > 0) ? buf[--bufp] : getchar();
14 | }
15 |
16 | void ungetch(int c)
17 | {
18 | if (bufp >= BUFSIZE)
19 | printf("ungetch: too many characters\n");
20 | else
21 | buf[bufp++] = c;
22 | }
23 |
24 | void ungetchs(char s[])
25 | {
26 | int len = strlen(s);
27 | while (len > 0) {
28 | ungetch(s[--len]);
29 | }
30 | }
31 |
32 | int getchOne(void)
33 | {
34 | if (value != EOF) {
35 | int temp = value;
36 | value = EOF;
37 | return temp;
38 | }
39 | else
40 | return getchar();
41 | }
42 |
43 | void ungetchOne(int c)
44 | {
45 | if (value != EOF)
46 | printf("ungetchOne: cannot ungetch more char\n");
47 | else
48 | value = c;
49 | }
50 |
--------------------------------------------------------------------------------
/chapter-7-input-and-output/cat-v1.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main(int argc, char *argv[])
4 | {
5 | FILE *fp;
6 | void filecopy(FILE *, FILE *);
7 |
8 | if (argc == 1)
9 | filecopy(stdin, stdout);
10 | else
11 | while (--argc > 0)
12 | if ((fp = fopen(*++argv, "r")) == NULL) {
13 | printf("cat: can't open %s\n", *argv);
14 | return 1;
15 | } else {
16 | filecopy(fp, stdout);
17 | fclose(fp);
18 | }
19 |
20 | return 0;
21 | }
22 |
23 | void filecopy(FILE *ifp, FILE *ofp)
24 | {
25 | int c;
26 |
27 | while ((c = getc(ifp)) != EOF)
28 | putc(c, ofp);
29 | }
30 |
31 |
--------------------------------------------------------------------------------
/chapter-7-input-and-output/cat-v2.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | main(int argc, char *argv[])
5 | {
6 | FILE *fp;
7 | void filecopy(FILE *, FILE *);
8 | char *prog = argv[0];
9 |
10 | if (argc == 1)
11 | filecopy(stdin, stdout);
12 | else
13 | while (--argc > 0)
14 | if ((fp = fopen(*++argv, "r")) == NULL) {
15 | fprintf(stderr, "%s: can't open %s\n", prog, *argv);
16 | exit(1);
17 | } else {
18 | filecopy(fp, stdout);
19 | fclose(fp);
20 | }
21 |
22 | if (ferror(stdout)) {
23 | fprintf(stderr, "%s: error writing stdout\n", prog);
24 | exit(2);
25 | }
26 |
27 | exit(0);
28 | }
29 |
30 | void filecopy(FILE *ifp, FILE *ofp)
31 | {
32 | int c;
33 |
34 | while ((c = getc(ifp)) != EOF)
35 | putc(c, ofp);
36 | }
37 |
38 |
--------------------------------------------------------------------------------
/chapter-7-input-and-output/minprintf.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | void minprintf(char *fmt, ...);
5 |
6 | int main()
7 | {
8 | minprintf("int: %d, double: %f, string: %s\n", 1, 0.123, "Hello");
9 |
10 | return 0;
11 | }
12 |
13 | void minprintf(char *fmt, ...)
14 | {
15 | va_list ap;
16 | char *p, *sval;
17 | int ival;
18 | double dval;
19 |
20 | va_start(ap, fmt);
21 | for (p = fmt; *p; p++) {
22 | if (*p != '%') {
23 | putchar(*p);
24 | continue;
25 | }
26 | switch(*++p) {
27 | case 'd':
28 | ival = va_arg(ap, int);
29 | printf("%d", ival);
30 | break;
31 | case 'f':
32 | dval = va_arg(ap, double);
33 | printf("%f", dval);
34 | break;
35 | case 's':
36 | for (sval = va_arg(ap, char *); *sval; sval++)
37 | putchar(*sval);
38 | break;
39 | default:
40 | putchar(*p);
41 | break;
42 | }
43 | }
44 | va_end(ap);
45 | }
46 |
47 |
--------------------------------------------------------------------------------
/chapter-7-input-and-output/scanf-sample.c:
--------------------------------------------------------------------------------
1 | #include
2 |
3 | main()
4 | {
5 | double sum, v;
6 |
7 | sum = 0;
8 | while (scanf("%1f", &v) == 1)
9 | printf("\t%.2f\n", sum += v);
10 | return 0;
11 | }
12 |
13 |
--------------------------------------------------------------------------------
/chapter-8-the-unix-system-interface/cp.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 | #include
5 | #include
6 |
7 | #define PERMS 0666
8 |
9 | void error(char *fmt, ...);
10 |
11 | main(int argc, char *argv[])
12 | {
13 | int f1, f2, n;
14 | char buf[BUFSIZ];
15 |
16 | if (argc != 3)
17 | error("usage: cp from to");
18 | if ((f1 = open(argv[1], O_RDONLY, 0)) == -1)
19 | error("cp: can't open %s", argv[1]);
20 | if ((f2 = open(argv[2], PERMS, 0)) == -1)
21 | error("cp: can't create %s, mode %03o", argv[2], PERMS);
22 |
23 | while ((n = read(f1, buf, BUFSIZ)) > 0)
24 | if (write(f2, buf, n) != n)
25 | error("cp: write error on file %s", argv[2]);
26 |
27 | return 0;
28 | }
29 |
30 | void error(char *fmt, ...)
31 | {
32 | va_list args;
33 |
34 | va_start(args, fmt);
35 | fprintf(stderr, "error: ");
36 | vfprintf(stderr, fmt, args);
37 | fprintf(stderr, "\n");
38 | va_end(args);
39 | exit(1);
40 | }
41 |
42 |
--------------------------------------------------------------------------------
/chapter-8-the-unix-system-interface/dirent.h:
--------------------------------------------------------------------------------
1 | typedef struct {
2 | long ino;
3 | char name[NAME_MAX+1];
4 | } Dirent;
5 |
6 | typedef struct {
7 | int fd;
8 | Dirent d;
9 | } DIR;
10 |
11 | DIR *opendir(char *dirname);
12 | Dirent *readdir(DIR *dfd);
13 | void closedir(DIR *dfd);
14 |
15 |
--------------------------------------------------------------------------------
/chapter-8-the-unix-system-interface/fopen.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 | #include
5 |
6 | //#define NULL 0
7 | #define EOF (-1)
8 | #define BUFSIZ 1024
9 | #define OPEN_MAX 20
10 |
11 | #define PERMS 0666
12 |
13 | typedef struct _iobuf {
14 | int cnt;
15 | char *ptr;
16 | char *base;
17 | int flag;
18 | int fd;
19 | } FILE;
20 |
21 | FILE _iob[OPEN_MAX];
22 |
23 | enum _flags {
24 | _READ = 01,
25 | _WRITE = 02,
26 | _UNBUF = 04,
27 | _EOF = 010,
28 | _ERR = 020
29 | };
30 |
31 | FILE *fopen(char *name, char *mode);
32 | int _fillbuf(FILE *fp);
33 |
34 | int main()
35 | {
36 | FILE *fp = fopen("fopen.c", "rw");
37 | assert(fp != NULL);
38 | return 0;
39 | }
40 |
41 | FILE *fopen(char *name, char *mode)
42 | {
43 | int fd;
44 | FILE *fp;
45 |
46 | if (*mode != 'r' && *mode != 'w' && *mode != 'a')
47 | return NULL;
48 | for (fp = _iob; fp < _iob + OPEN_MAX; fp++)
49 | if ((fp->flag & (_READ | _WRITE)) == 0)
50 | break;
51 | if (fp >= _iob + OPEN_MAX)
52 | return NULL;
53 |
54 | if (*mode == 'w')
55 | fd = creat(name, PERMS);
56 | else if (*mode == 'a') {
57 | if ((fd = open(name, O_WRONLY, 0)) == -1)
58 | fd = creat(name, PERMS);
59 | lseek(fd, 0L, 2);
60 | } else
61 | fd = open(name, O_RDONLY, 0);
62 | if (fd == -1)
63 | return NULL;
64 | fp->fd = fd;
65 | fp->cnt = 0;
66 | fp->base = NULL;
67 | fp->flag = (*mode == 'r') ? _READ : _WRITE;
68 | return fp;
69 | }
70 |
71 | int _fillbuf(FILE *fp)
72 | {
73 | int bufsize;
74 |
75 | if ((fp->flag & (_READ | EOF | _ERR)) != _READ)
76 | return EOF;
77 | bufsize = (fp->flag & _UNBUF) ? 1 : BUFSIZ;
78 | if (fp->base == NULL)
79 | if ((fp->base = (char *) malloc(bufsize)) == NULL)
80 | return EOF;
81 | fp->ptr = fp->base;
82 | fp->cnt = read(fp->fd, fp->ptr, bufsize);
83 | if (--fp->cnt < 0) {
84 | if (fp->cnt == -1)
85 | fp->flag |= _EOF;
86 | else
87 | fp->flag |= _ERR;
88 | fp->cnt = 0;
89 | return EOF;
90 | }
91 | return (unsigned char) *fp->ptr++;
92 | }
93 |
94 | FILE _iob[OPEN_MAX] = {
95 | { 0, (char *) 0, (char *) 0, _READ, 0 },
96 | { 0, (char *) 0, (char *) 0, _WRITE, 1 },
97 | { 0, (char *) 0, (char *) 0, _WRITE | _UNBUF, 2 },
98 | };
99 |
100 |
--------------------------------------------------------------------------------
/chapter-8-the-unix-system-interface/fsize.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 | #include
4 | #include
5 | #include
6 | #include
7 | #include "dirent.h"
8 |
9 | void fsize(char *);
10 |
11 | main (int argc, char **argv)
12 | {
13 | if (argc == 1)
14 | fsize(".");
15 | else
16 | while (--argc > 0)
17 | fsize(*++argv);
18 | return 0;
19 | }
20 |
21 | int stat(char *, struct stat *);
22 | void dirwalk(char *, void (*fcn)(char *));
23 |
24 | void fsize(char *name)
25 | {
26 | struct stat stbuf;
27 |
28 | if (stat(name, &stbuf) == -1) {
29 | fprintf(stderr, "fsize: can't access %s\n", name);
30 | return;
31 | }
32 | if ((stbuf.st_mode & S_IFMT) == S_IFDIR)
33 | dirwalk(name, fsize);
34 | printf("%8ld %s\n", stbuf.st_size, name);
35 | }
36 |
37 | #define MAX_PATH 1024
38 |
39 | void dirwalk(char *dir, void (*fcn)(char *))
40 | {
41 | char name[MAX_PATH];
42 | Dirent *dp;
43 | DIR *dfd;
44 |
45 | if ((dfd = opendir(dir)) == NULL) {
46 | fprintf(stderr, "dirwalk: can't open %s\n", dir);
47 | return;
48 | }
49 | while ((dp = readdir(dfd)) != NULL) {
50 | if (strcmp(dp->name, ".") == 0
51 | || strcmp(dp->name, "..") == 0)
52 | continue;
53 | if (strlen(dir) + strlen(dp->name) + 2 > sizeof(name))
54 | fprintf(stderr, "dirwalk: name %s/%s too long\n",
55 | dir, dp->name);
56 | else {
57 | sprintf(name, "%s/%s", dir, dp->name);
58 | (*fcn)(name);
59 | }
60 | }
61 | closedir(dfd);
62 | }
63 |
64 | int fstat(int fd, struct stat *);
65 |
66 | DIR *opendir(char *dirname)
67 | {
68 | int fd;
69 | struct stat stbuf;
70 | DIR *dp;
71 |
72 | if ((fd = open(dirname, O_RDONLY, 0)) == -1
73 | || fstat(fd, &stbuf) == -1
74 | || (stbuf.st_mode & S_IFMT) != S_IFDIR
75 | || (dp = (DIR *) malloc(sizeof(DIR))) == NULL)
76 | return NULL;
77 | dp->fd = fd;
78 | return dp;
79 | }
80 |
81 | void closedir(DIR *dp)
82 | {
83 | if (dp) {
84 | close(dp->fd);
85 | free(dp);
86 | }
87 | }
88 |
89 | #include
90 |
91 | Dirent *readdir(DIR *dp)
92 | {
93 | struct direct dirbuf;
94 | static Dirent d;
95 |
96 | while (read(dp->fd, (char *) &dirbuf, sizeof(dirbuf))
97 | == sizeof(dirbuf)) {
98 | if (dirbuf.d_ino == 0)
99 | continue;
100 | d.ino = dirbuf.d_ino;
101 | strncpy(d.name, dirbuf.d_name, DIRSIZ);
102 | d.name[DIRSIZ] = '\0';
103 | return &d;
104 | }
105 | return NULL;
106 | }
107 |
108 |
--------------------------------------------------------------------------------
/chapter-8-the-unix-system-interface/malloc.c:
--------------------------------------------------------------------------------
1 | typedef long Align; /* for alignment to long boundary */
2 |
3 | union header { /* block header: */
4 | struct {
5 | union header *ptr; /* next block if on free list */
6 | unsigned size; /* size of this block */
7 | } s;
8 | Align x; /* force alignment of blocks */
9 | };
10 |
11 | typedef union header Header;
12 |
13 |
14 | static Header base; /* empty list to get started */
15 | static Header *freep = NULL; /* start of free list */
16 |
17 | /* malloc: general-purpose storage allocator */
18 | void *malloc(unsigned nbytes)
19 | {
20 | Header *p, *prevp;
21 | Header *morecore(unsigned);
22 | unsigned nunits;
23 |
24 | nunits = (nbytes+sizeof(Header)-1) / sizeof(Header) + 1;
25 | if ((prevp = freep) == NULL) { /* no free list yet */
26 | base.s.ptr = freep = prevp = &base;
27 | base.s.size = 0;
28 | }
29 | for (p = prevp->s.ptr; ; prevp = p, p = p->s.ptr) {
30 | if (p->s.size >= nunits) { /* big enough */
31 | if (p->s.size == nunits) /* exactly */
32 | prevp->s.ptr = p->s.ptr;
33 | else { /* allocate tail end */
34 | p->s.size -= nunits;
35 | p += p->s.size;
36 | p->s.size = nunits;
37 | }
38 | freep = prevp;
39 | return (void *)(p+1);
40 | }
41 | if (p == freep) /* wrapped around free list */
42 | if ((p = morecore(nunits)) == NULL)
43 | return NULL; /* none left */
44 | }
45 | }
46 |
47 | #define NALLOC 1024 /* minimum units to request */
48 |
49 | /* morecore: ask system for more memory */
50 | static Header *morecore(unsigned nu)
51 | {
52 | char *cp, *sbrk(int);
53 | Header *up;
54 |
55 | if (nu < NALLOC)
56 | nu = NALLOC;
57 | cp = sbrk(nu * sizeof(Header));
58 | if (cp == (char *) - 1) /* no space at all */
59 | return NULL;
60 | up = (Header *) cp;
61 | up->s.size = nu;
62 | free((void *)(up+1));
63 | return freep;
64 | }
65 |
66 | /* free: put block ap in free list */
67 | void free(void *ap)
68 | {
69 | Header *bp, *p;
70 |
71 | bp = (Header *)ap - 1;
72 | for (p = freep; !(bp > p && bp < p->s.ptr); p = p->s.ptr)
73 | if (p >= p->s.ptr && (bp > p || bp < p->s.ptr))
74 | break;
75 |
76 | if (bp + bp->s.size == p->s.ptr) {
77 | bp->s.size += p->s.ptr->s.size;
78 | bp->s.ptr = p->s.ptr->s.ptr;
79 | } else
80 | bp->s.ptr = p->s.ptr;
81 |
82 | if (p + p->s.size == bp) {
83 | p->s.size += bp->s.size;
84 | p->s.ptr = bp->s.ptr;
85 | } else
86 | p->s.ptr = bp;
87 | freep = p;
88 | }
89 |
90 |
--------------------------------------------------------------------------------
/chapter-8-the-unix-system-interface/sys-copy.c:
--------------------------------------------------------------------------------
1 | #include
2 | #include
3 |
4 | main()
5 | {
6 | char buf[BUFSIZ];
7 | int n;
8 |
9 | while ((n = read(0, buf, BUFSIZ)) > 0)
10 | write(1, buf, n);
11 | return 0;
12 | }
13 |
14 |
--------------------------------------------------------------------------------