├── README.md
└── link


/README.md:
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1 | # doubly-linked-list
2 | This C program implements a doubly linked list with functions to insert nodes at the end (`insert`), at the beginning (`insertbeg`), after a given node (`insertafter`), before a given node (`insertbefore`), and at a specific position (`insertpos`). It also includes a `display` function to print the list.
3 | 


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/link:
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  1 | #include <stdio.h>
  2 | #include <stdlib.h>
  3 | struct Node{
  4 |     int data;
  5 |     struct Node *next;
  6 |     struct Node *prev;
  7 | };
  8 | typedef struct Node node;
  9 | node *head=NULL;
 10 | void insert(int d){
 11 |     node*newnode=(node *)malloc(sizeof(node));
 12 |     newnode->prev=NULL;
 13 |     newnode->data=d;
 14 |     newnode->next=NULL;
 15 |     if(head==NULL){
 16 |         head=newnode;
 17 |     }
 18 |     else{
 19 |         node*temp=head;
 20 |     while(temp->next!=NULL){
 21 |         temp=temp->next;
 22 |     }
 23 |         temp->next=newnode;
 24 |         newnode->prev=temp;
 25 |     }
 26 | }
 27 | void insertbeg(int d){
 28 |     node *newnode=(node*)malloc(sizeof(node));
 29 |     newnode->data=d;
 30 |     newnode->next=head;
 31 |     head->prev=newnode;
 32 |     newnode->prev=NULL;
 33 |     head=newnode;
 34 | }
 35 | void insertafter(int x,int d){
 36 |     node* newnode=(node*)malloc(sizeof(node));
 37 |     newnode->data=d;
 38 |     newnode->next=NULL;
 39 |     newnode->prev=NULL;
 40 |     if(head==NULL){
 41 |         printf("\n Empty");
 42 |     return;}
 43 |     node *temp=head;
 44 |     while(temp->data!=x){
 45 |         temp=temp->next;
 46 |     }
 47 |     newnode->next=temp->next;
 48 |     temp->next->prev=newnode;
 49 |     temp->next=newnode;
 50 |     newnode->prev=temp;
 51 | }
 52 | void insertbefore(int x,int d){
 53 |     node *newnode=(node*)malloc(sizeof(node));
 54 |     newnode->data=d;
 55 |     newnode->next=NULL;
 56 |     newnode->prev=NULL;
 57 |     
 58 |     if(head==NULL){
 59 |         printf("\n Empty");
 60 |     }
 61 |     else{
 62 |         node*temp=head;
 63 |         node*prev=NULL;
 64 |         while(temp->data!=x){
 65 |             prev=temp;
 66 |             temp=temp->next;
 67 |         }
 68 |         newnode->next=temp;
 69 |         prev->next=newnode;
 70 |         newnode->prev=prev;
 71 |         temp->prev=newnode;
 72 |     }
 73 | }
 74 | void insertpos(int p,int d){
 75 |     node*newnode=(node*)malloc(sizeof(node));
 76 |     newnode->data=d;
 77 |     newnode->next=NULL;
 78 |     newnode->prev=NULL;
 79 |     int current=0;
 80 |     if(head==NULL){
 81 |         printf("\n Empty");
 82 |     }
 83 |     else{
 84 |         node*temp=head;
 85 |         node*prev=NULL;
 86 |         if(p==0){
 87 |             insertbeg(d);
 88 |         return;}
 89 |         while(temp!=NULL && current!= p) {
 90 |             prev = temp;
 91 |             temp = temp->next;
 92 |             current++;
 93 |         }
 94 |         
 95 |         newnode->prev = prev;
 96 |         newnode->next = temp;
 97 |         temp->prev = newnode;
 98 |         prev->next = newnode;
 99 |     }
100 | }
101 | void display(){
102 |     node *temp=head;
103 |     while(temp!=NULL){
104 |         printf("%d->",temp->data);
105 |         temp=temp->next;
106 |     }
107 |     printf("NULL");
108 | }
109 | int main() {
110 |     insert(1);
111 |     insert(2);
112 |     insertbeg(3);
113 |     insertafter(1,4);
114 |     insertbefore(4,5);
115 |     insertpos(2,6);
116 |     display();
117 |     return 0;
118 | }
119 | 


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