├── 8. File operation
    ├── Naz.txt
    └── Fileop.java
├── 1. String Palindrome
    └── Palindrome.java
├── 6. Tokenization
    └── Token.java
├── 2. String Frequency
    └── Frequency.java
├── README.md
├── 5. Polymorphism
    └── Polymorphism.java
├── 9. Thread synchronization
    └── Threaddemo.java
├── 7. Exception handling
    └── Exc.java
├── 4. Inheritance
    └── InheritanceDemo.java
├── 3. Matrix Multiplication
    └── Matrix.java
└── _10. Calculator
    └── Calc.java


/8. File operation/Naz.txt:
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1 | hello


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/1. String Palindrome/Palindrome.java:
--------------------------------------------------------------------------------
 1 | import java.util.Scanner;
 2 | 
 3 | 
 4 | public class Palindrome{
 5 | 
 6 | 	public static void main(String[] args){
 7 | 	
 8 | 		Scanner scan = new Scanner(System.in);
 9 | 	
10 | 		System.out.print("Enter the string: ");
11 | 		String str = scan.nextLine();
12 | 		
13 | 		String rev = "";
14 | 	
15 | 		for (int i = str.length() - 1 ; i >= 0 ; i--){
16 | 			rev = rev + str.charAt(i);}
17 | 	
18 | 	
19 | 		if (rev.equalsIgnoreCase(str))
20 | 			System.out.println("Palindrome");
21 | 		
22 | 		else System.out.println("Not a Palindrome");
23 | 	
24 | 		scan.close();
25 | 		
26 | 	}	
27 | 		
28 | }
29 | 


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/6. Tokenization/Token.java:
--------------------------------------------------------------------------------
 1 | import java.util.*;
 2 | public class Token {
 3 |     
 4 |     public static void main(String[] args) {
 5 |     
 6 |      Scanner sc=new Scanner(System.in);
 7 |      int x;
 8 |      int sum=0;
 9 |      System.out.println("ENTER THE DIGITS WITH GAP");
10 |      String n=sc.nextLine();
11 |      StringTokenizer st=new StringTokenizer(n," ");
12 |      while(st.hasMoreTokens()){
13 |          String temp=st.nextToken();
14 |          x= Integer.parseInt(temp);
15 |          System.out.println(x);
16 |          sum=sum+x;
17 |      }
18 |       System.out.println("sum= "+sum);
19 |       sc.close();
20 |     }
21 | }
22 |     
23 | 
24 | 


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/2. String Frequency/Frequency.java:
--------------------------------------------------------------------------------
 1 | import java.util.Scanner;
 2 | import java.io.IOException;
 3 | public class Frequency {
 4 | 
 5 | 
 6 |     public static void main(String[] args) {
 7 |          Scanner obj=new Scanner(System.in);
 8 |          System.out.println("Enter the string");
 9 |          String str = obj.nextLine();
10 |          System.out.println("Enter a character");
11 |          String k = obj.nextLine();
12 |          int l= str.length();
13 |          int count=0;
14 |          for(int i=0;i<l;i++)
15 |          {
16 |              if (str.charAt(i) == k.charAt(0))
17 |              count++;
18 |          }
19 |          System.out.println("The frequency of the given character is "+count);
20 |     }
21 | }
22 | 
23 | 


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/README.md:
--------------------------------------------------------------------------------
 1 | # Object Oriented Programming using Java Lab
 2 | Based on 2019 KTU Scheme
 3 | 
 4 | # Contents
 5 | 
 6 | ##### 1) [String Palindrome](/1.%20String%20Palindrome/Palindrome.java)
 7 | 
 8 | ##### 2) [Frequency of a given character](/2.%20String%20Frequency/Frequency.java)
 9 | 
10 | ##### 3) [Matrix Multiplication](/3.%20Matrix%20Multiplication/Matrix.java)
11 | 
12 | ##### 4) [Inheritance](/4.%20Inheritance/InheritanceDemo.java)
13 | 
14 | ##### 5) [Polymorphism](/5.%20Polymorphism/Polymorphism.java)
15 | 
16 | ##### 6) [Tokenization](/6.%20Tokenization/Token.java)
17 | 
18 | ##### 7) [Exception Handling](7.%20Exception%20handling/Exc.java)
19 | 
20 | ##### 8) [File Operation](8.%20File%20operation/Fileop.java)
21 | 
22 | ##### 9) [Thread Synchronization](9.%20Thread%20synchronization/Threaddemo.java)
23 | 
24 | ##### 10) [Calculator (Swing)](_10.%20Calculator/Calc.java)
25 | 


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/5. Polymorphism/Polymorphism.java:
--------------------------------------------------------------------------------
 1 | import java.util.Scanner;
 2 | 
 3 | 
 4 | abstract class Shape{
 5 |    abstract int numberofsides();
 6 | }
 7 | 
 8 | class Rectangle extends Shape{
 9 |     int numberofsides(){
10 |         return 4;
11 |     }
12 | }
13 | 
14 | class Triangle extends Shape{
15 |     int numberofsides(){
16 |         return 3;
17 |     }
18 | }
19 | 
20 | class Hexagon extends Shape{
21 |     int numberofsides(){
22 |         return 6;
23 |     }
24 | }
25 | 
26 | 
27 | public class Polymorphism {
28 | 
29 |     public static void main(String[] args) {
30 |          Shape sc;
31 |         sc=new Rectangle();
32 |         System.out.println("Rectangle:"+sc.numberofsides());
33 |         
34 |         sc=new Triangle();
35 |         System.out.println("Triangle:"+sc.numberofsides());
36 |          
37 |         sc=new Hexagon();
38 |         System.out.println("hexagon:"+sc.numberofsides());   
39 |     }
40 |     
41 | }
42 | 


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/9. Thread synchronization/Threaddemo.java:
--------------------------------------------------------------------------------
 1 | class First{
 2 |     synchronized public void display(String msg){
 3 |         System.out.print("["+msg);
 4 |         try{
 5 |         Thread.sleep(1000);
 6 |         }catch(InterruptedException e){
 7 |             e.printStackTrace();
 8 |         } System.out.println("]");
 9 |     } 
10 | }
11 | 
12 | class Second extends Thread{
13 |     String msg;
14 |     First fobj;
15 |     
16 |     Second(First fp,String str){
17 |         fobj=fp;
18 |         msg=str;
19 |         start();
20 |       //  run();
21 |     }
22 |     
23 |     public void run(){
24 |         fobj.display(msg);
25 |     }
26 | }
27 | 
28 | public class Threaddemo {
29 | 
30 |     public static void main(String[] args) {
31 |     First fnew = new First();
32 |     Second ss = new Second(fnew,"Welcome");
33 |     Second ss1 = new Second(fnew,"new");
34 |     Second ss2 = new Second(fnew,"programmer");
35 |     
36 |     }
37 |     
38 | }
39 | 


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/7. Exception handling/Exc.java:
--------------------------------------------------------------------------------
 1 | import java.util.Scanner;
 2 | 
 3 | public class Exc {
 4 |     
 5 | static void div(int num,int den) throws ArithmeticException
 6 |   {
 7 |     if(den==0)
 8 |         
 9 |         throw new ArithmeticException("division by zero is not possible");
10 | 
11 |      else
12 |         System.out.println("The result is : "+num/den);
13 |         
14 |      }
15 |     
16 |     public static void main(String[] args) {
17 |        try{
18 |             Scanner sc=new Scanner(System.in);
19 |             System.out.print("Enter the numerator : "); 
20 |                     int num=sc.nextInt();
21 |                     System.out.print("Enter the denominator : ");
22 |                     int den=sc.nextInt();
23 |                     div( num,den);
24 |        }catch(Exception e)
25 |        {
26 |            System.out.println(e);
27 |        }
28 |        finally{System.out.println("Final block has been executed");}
29 |     }
30 |     
31 | }
32 | 


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/8. File operation/Fileop.java:
--------------------------------------------------------------------------------
 1 | import java.io.*;
 2 | import java.util.*;
 3 | 
 4 | public class Fileop {
 5 | 
 6 |     public static void main(String[] args) {
 7 |        try{
 8 |            File obj= new File("Naz.txt");
 9 |            obj.createNewFile();
10 |            System.out.println("File created Successfully "+obj.getName());  
11 |            Scanner sc = new Scanner(System.in);
12 |            System.out.println("Enter the text to be written to the file : "); 
13 |            String t=sc.nextLine();
14 |            FileWriter fw=new FileWriter("Naz.txt");
15 |            fw.write(t);
16 |            fw.close();
17 |            System.out.println("Wrote to the file successfully");
18 |            File read = new File("Naz.txt");
19 |            Scanner cs = new Scanner(read);
20 |            while(cs.hasNextLine())
21 |            {
22 |                String b = cs.nextLine();
23 |                System.out.println(b);
24 |            }
25 |            cs.close();
26 |            System.out.println("Read from file successfully");
27 |        } catch (Exception e){
28 |            System.out.println("Something went Wrong");
29 |        }
30 |     }
31 |     
32 | }
33 | 
34 | 


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/4. Inheritance/InheritanceDemo.java:
--------------------------------------------------------------------------------
 1 | import java.util.Scanner;
 2 | 
 3 |  class Employee{
 4 |     int age, phonenumber,salary;
 5 |     String name,address;
 6 |     public void salary(int a)
 7 |     {
 8 |    
 9 |        System.out.println("Salary is " +a);
10 |     }
11 | }
12 |   class Officer extends Employee{
13 |       
14 |       String specialization;
15 |      
16 |     }
17 |     class Manager extends Employee{
18 |      
19 |         String department;
20 |     }
21 | 
22 | 
23 | public class InheritanceDemo {
24 | 
25 |    
26 |     public static void main(String[] args) {
27 |       
28 |        Scanner sc=new Scanner(System.in);
29 |        Scanner obj=new Scanner(System.in);
30 |        Officer o=new Officer();
31 |        Manager m=new Manager();
32 |        System.out.println("ENTER THE NAME OF OFFICER:");
33 |        o.name=sc.nextLine();
34 |         System.out.println("ENTER THE address OF THE OFFICER:");
35 |        o.address=sc.nextLine();
36 |        System.out.println("ENTER THE Specialization OF THE OFFICER:");
37 |        o.specialization=sc.nextLine();
38 |        System.out.println("ENTER THE age OF THE OFFICER :");
39 |        o.age=sc.nextInt();
40 |        System.out.println("ENTER THE SALARY OF THE OFFICER:");
41 |        o.salary=sc.nextInt();
42 |        System.out.println("THE NAME is "+o.name);
43 |        System.out.println("THE AGE IS  "+o.age);
44 |        System.out.println("THE address is "+o.address);
45 |        o.salary(o.salary);
46 |        System.out.println();
47 |        System.out.println("ENTER THE NAME OF MANAGER: ");
48 |        m.name=obj.nextLine();
49 |        System.out.println("ENTER THE address OF THE MANAGER: ");
50 |        m.address=obj.nextLine();
51 |        System.out.println("ENTER THE department OF THE MANAGER: ");
52 |        m.department=obj.nextLine();
53 |        System.out.println("ENTER THE age OF THE MANAGER : ");
54 |        m.age=obj.nextInt();
55 |        System.out.println("ENTER THE SALARY OF THE MANAGER: ");
56 |        m.salary=obj.nextInt();
57 |        System.out.println("THE NAME is "+m.name);
58 |        System.out.println("THE AGE IS  "+m.age);
59 |        System.out.println("THE address is "+m.address);
60 |         System.out.println("THE department is "+ m.department);
61 |        m.salary(m.salary);
62 |     }
63 | }
64 | 


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/3. Matrix Multiplication/Matrix.java:
--------------------------------------------------------------------------------
 1 | import java.util.Scanner;
 2 | import java.io.IOException;
 3 | public class Matrix {
 4 | 
 5 |    
 6 |     public static void main(String[] args) {
 7 |         
 8 |         Scanner sc= new Scanner(System.in);    
 9 |         System.out.println("ENTER THE ROW OF FIRST MATRIX");
10 |         int row1 = sc.nextInt();
11 |         System.out.println("ENTER THE COLUMN OF FIRST MATRIX");
12 |         int col1 = sc.nextInt();
13 |         System.out.println("ENTER THE ROW OF SECOND MATRIX");
14 |         int row2 = sc.nextInt();
15 |         System.out.println("ENTER THE COLUMN OF SECOND MATRIX");
16 |         int col2 = sc.nextInt();
17 |         if(col1!=row2)
18 |         {
19 |           System.out.println("multiplication is not possible");
20 |           return;
21 |         }
22 |         
23 |        int i,j,k;
24 |            int [][] a = new int [row1][col1];
25 |            int [][] b = new int [row2][col2];
26 |            int [][] c = new int [col1][row2];
27 |             try{
28 |           System.out.println("ENTER THE ELEMENTS OF FIRST MATRIX");
29 |           for( i=0;i<row1;i++)
30 |           {
31 |               for( j=0;j<col1;j++)
32 |               {
33 |                   a[i][j]=sc.nextInt();
34 |                   
35 |           }
36 |         }
37 |           System.out.println("ENTER THE ELEMENTS OF SECOND MATRIX");
38 |           for(i = 0;i<row2;i++)
39 |           {
40 |               for(j=0;j<col2;j++)
41 |               {
42 |                   b[i][j]=sc.nextInt();
43 |               }
44 |           }
45 |           System.out.println("The multiplied metrix is:");
46 |           for( i=0;i<row1;i++)
47 |           {
48 |               for( j=0;j<col2;j++)
49 |               {
50 |                   c[i][j]=0;
51 |  
52 |               for( k=0;k<col1;k++)
53 |               {
54 |                   c[i][j]+=a[i][k]*b[k][j];
55 |               }
56 |               }
57 |           }
58 |         
59 |       
60 |             for(i=0;i<row1;i++)
61 |             {
62 |                 for (j=0;j<col2;j++)
63 |                 {
64 |                     System.out.print(c[i][j] +" ");
65 |                 }
66 |                 System.out.println();
67 |         
68 |                 
69 |             }
70 |     }catch(Exception e){}
71 |         
72 |     }
73 | }
74 | 
75 | 


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/_10. Calculator/Calc.java:
--------------------------------------------------------------------------------
  1 | import javax.swing.*;
  2 | import java.awt.event.*;
  3 | 
  4 | public class Calc extends JFrame implements ActionListener{
  5 |     private JTextField t1;
  6 |     private JButton b1;
  7 |     private JButton b2;
  8 |     private JButton b3;
  9 |     private JButton b4;
 10 |     private JButton b5;
 11 |     private JButton b6;
 12 |     private JButton b7;
 13 |     private JButton b8;
 14 |     private JButton b9;
 15 |     private JButton b10;
 16 |     private JButton b11;
 17 |     private JButton b12;
 18 |     private JButton b13;
 19 |     private JButton b14;
 20 |     private JButton b15;
 21 |     private JButton b16;
 22 |     private JButton b17;
 23 |     private Integer res;
 24 |     private String operation;
 25 |     
 26 |     
 27 |     Calc()
 28 |     {
 29 |         setLayout(null);
 30 |         setSize(400,400);
 31 |         t1=new JTextField();
 32 |         t1.setBounds(100,100,200,30);
 33 |         b1=new JButton("1");
 34 |         b1.setBounds(100,140,50,30);
 35 |         b2=new JButton("2");
 36 |         b2.setBounds(150,140,50,30);
 37 |         b3=new JButton("3");
 38 |         b3.setBounds(200,140,50,30);
 39 |         b4=new JButton("+");
 40 |         b4.setBounds(250,140,50,30);
 41 |         b5=new JButton("4");
 42 |         b5.setBounds(100,170,50,30);
 43 |         b6=new JButton("5");
 44 |         b6.setBounds(150,170,50,30);
 45 |         b7=new JButton("6");
 46 |         b7.setBounds(200,170,50,30);
 47 |         b8=new JButton("-");
 48 |         b8.setBounds(250,170,50,30);
 49 |         b9=new JButton("7");
 50 |         b9.setBounds(100,200,50,30);
 51 |         b10=new JButton("8");
 52 |         b10.setBounds(150,200,50,30);
 53 |         b11=new JButton("9");
 54 |         b11.setBounds(200,200,50,30);
 55 |         b12=new JButton("*");
 56 |         b12.setBounds(250,200,50,30);
 57 |         b13=new JButton("/");
 58 |         b13.setBounds(100,230,50,30);
 59 |         b14=new JButton("%");
 60 |         b14.setBounds(150,230,50,30);
 61 |         b15=new JButton("=");
 62 |         b15.setBounds(200,230,50,30);
 63 |         b16=new JButton("C");
 64 |         b16.setBounds(250,230,50,30);
 65 |         b17=new JButton("0");
 66 |         b17.setBounds(100,260,200,30);
 67 |         add(t1);
 68 |         add(b1);
 69 |         add(b2);
 70 |         add(b3);
 71 |         add(b4);
 72 |         add(b5);
 73 |         add(b6);
 74 |         add(b7);
 75 |         add(b8);
 76 |         add(b9);
 77 |         add(b10);
 78 |         add(b11);
 79 |         add(b12);
 80 |         add(b13);
 81 |         add(b14);
 82 |         add(b15);
 83 |         add(b16);
 84 |         add(b17);
 85 |         b1.addActionListener(this);
 86 |         b2.addActionListener(this);
 87 |         b3.addActionListener(this);
 88 |         b4.addActionListener(this);
 89 |         b5.addActionListener(this);
 90 |         b6.addActionListener(this);
 91 |         b7.addActionListener(this);
 92 |         b8.addActionListener(this);
 93 |         b9.addActionListener(this);
 94 |         b10.addActionListener(this);
 95 |         b11.addActionListener(this);
 96 |         b12.addActionListener(this);
 97 |         b13.addActionListener(this);
 98 |         b14.addActionListener(this);
 99 |         b15.addActionListener(this);
100 |         b16.addActionListener(this);
101 |         b17.addActionListener(this);
102 |        
103 |         
104 |         
105 |         
106 |     }
107 |     public void doAction(String op)
108 |     {
109 |         if(operation==null)
110 |         {
111 |             operation=op;
112 |             res=Integer.parseInt(t1.getText());
113 |             t1.setText("");
114 |         }
115 |         else
116 |         {
117 |          switch(operation)
118 |          {
119 |              case "+":
120 |                  res=res+Integer.parseInt(t1.getText());
121 |                  break;
122 |              case "-":
123 |                  res=res-Integer.parseInt(t1.getText());
124 |                  break;
125 |              case "*":
126 |                  res=res*Integer.parseInt(t1.getText());
127 |                  break;
128 |              case "%":
129 |                  res=res%Integer.parseInt(t1.getText());
130 |                  break;
131 |              case "/":
132 |                  try
133 |                  {
134 |                  if(t1.getText().equals("0"))
135 |                  {
136 |                      throw new ArithmeticException("Division by 0");
137 |                      
138 |                  }
139 |                  else
140 |                  {
141 |                     res = res/Integer.parseInt(t1.getText());
142 |                  }
143 |                  
144 |                 
145 |                  }catch(Exception e){
146 |                  t1.setText(e.getMessage());
147 |                  operation=null;
148 |                  res=0;
149 |                  }
150 |                  break;
151 |                  
152 |          }
153 |          if(op.equals("="))
154 |          {
155 |              t1.setText(res.toString());
156 |              res=0;
157 |              operation=null;
158 |          }
159 |          else
160 |          {
161 |              operation=op;
162 |              t1.setText("");
163 |          }
164 |         }
165 |     }
166 |     public void actionPerformed(ActionEvent e)
167 |     {
168 |         if(e.getSource()==b1)
169 |         {
170 |             t1.setText(t1.getText()+"1");
171 |         }
172 |         else if(e.getSource()==b2)
173 |         {
174 |             t1.setText(t1.getText()+"2");
175 |         }
176 |         else if(e.getSource()==b3)
177 |         {
178 |             t1.setText(t1.getText()+"3");
179 |         }
180 |         else if(e.getSource()==b5)
181 |         {
182 |             t1.setText(t1.getText()+"4");
183 |         }
184 |         else if(e.getSource()==b6)
185 |         {
186 |             t1.setText(t1.getText()+"5");
187 |         }
188 |         else if(e.getSource()==b7)
189 |         {
190 |             t1.setText(t1.getText()+"6");
191 |         }
192 |         else if(e.getSource()==b9)
193 |         {
194 |             t1.setText(t1.getText()+"7");
195 |         }
196 |         else if(e.getSource()==b10)
197 |         {
198 |             t1.setText(t1.getText()+"8");
199 |         }
200 |         else if(e.getSource()==b11)
201 |         {
202 |             t1.setText(t1.getText()+"9");
203 |         }
204 |         else if(e.getSource()==b17)
205 |         {
206 |             t1.setText(t1.getText()+"0");
207 |         }
208 |         else if(e.getSource()==b4)
209 |         {
210 |             doAction("+");
211 |         }
212 |         else if(e.getSource()==b8)
213 |         {
214 |             doAction("-");
215 |         }
216 |         else if(e.getSource()==b12)
217 |         {
218 |             doAction("*");
219 |         }
220 |         else if(e.getSource()==b13)
221 |         {
222 |             doAction("/");
223 |         }
224 |         else if(e.getSource()==b14)
225 |         {
226 |             doAction("%");
227 |         }
228 |         else if(e.getSource()==b15)
229 |         {
230 |             doAction("=");
231 |         }
232 |         else if(e.getSource()==b16)
233 |         {
234 |             t1.setText("");
235 |             operation = null;
236 |             res = 0;
237 |         }
238 |     }
239 |     
240 |     public static void main(String[] args) {
241 |         
242 |         new Calc().setVisible(true);
243 |     }
244 |   
245 | }


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