Program : Doubly Linked List – Insertion

Program : Doubly Linked List – Insertion

// Insertion in doubly linked list (Insert First, Last and node at desire position)

#include<stdio.h>

#include<conio.h>

#include<stdlib.h>

struct link

{

          int no;

          struct link *next;

          struct link *pre;

};

struct link *node,*start,*new1;

void create_link(struct link *node);

void display(struct link *node);

void insert_first(struct link *node);

void insert_last(struct link *node);

void insert_desireposition(struct link *node);

void main()

{

          int ch;

          clrscr();

          do

          {

          printf("\n Doubly Linked List");

          printf("\n---------------------------");

          printf("\n 1. Create Linked list");

          printf("\n 2. Traverse Linked list");

          printf("\n 3. Insert First node");

          printf("\n 4. Insert Last node");

          printf("\n 5. Insert node at Desire Position");

          printf("\n 6. Exit");

          printf("\n-----------------------------");

                   printf("\n Enter your choice:-");

                   scanf("%d",&ch);

                   switch(ch)

                   {

                             case 1:

                                      node=(struct link *)malloc(sizeof(struct link));

                                      create_link(node);

                                      printf("\n List is as follow");

                                      display(node);

                                      break;

                             case 2:

                                      printf("\n Output\n");

                                      display(node);

                                      break;

                             case 3:

                                      insert_first(node);

                                      printf("\n After Inserting First Node");

                                      display(node);

                                      break;

                             case 4:

                                      insert_last(node);

                                      printf("\n After Inserting Last Node");

                                      display(node);

                                      break;

                             case 5:

                                      insert_desireposition(node);

                                      printf("\n After Inserting At Desire Position");

                                      display(node);

                                      break;

                             case 6:

                                      exit(0);

                                      break;

                             default:

                                      printf("\n Wrong Choice");

                   }

          }while(ch!=6);

          getch();

}

void create_link(struct link *node)

{

          char ans;

          start->next=NULL;

          start->pre=NULL;

          node=start;

          fflush(stdin);

          printf("\n Enter 'n' for break:-");

          ans=getchar();

          while(ans!='n')

          {

                   node->next=(struct link *)malloc(sizeof(struct link));

                   node->next->pre=node;

                   node=node->next;

                   printf("\n Enter data for node:-");

                   scanf("%d",&node->no);

                   node->next=NULL;

                   fflush(stdin);

                   printf("\n Enter 'n' for break:-");

                   ans=getchar();

          }

}

void display(struct link *node)

{

          node=start->next;

          while(node)

          {

                   printf("\n  %d",node->no);

                   node=node->next;

          }

}

void insert_first(struct link *node)

{

          node=start->next;

          new1=(struct link *)malloc(sizeof(struct link));

          printf("\n Insert data for first node:-");

          scanf("%d",&new1->no);

          node->pre->next=new1;

          new1->pre=node->next;

          new1->next=node;

          node->pre=new1;

}

void insert_last(struct link *node)

{

          node=start->next;

          while(node->next)

          {

                   node=node->next;

          }

          new1=(struct link *)malloc(sizeof(struct link));

          printf("\n Insert data for last node:-");

          scanf("%d",&new1->no);

          node->next=new1;

          new1->pre=node;

          new1->next=NULL;

}

void insert_desireposition(struct link *node)

{

          int node_no=1,insert_no,flag=0;

          node=start->next;

          printf("\n Enter position where you want to insert new node :-");

          scanf("%d",&insert_no);

          while(node)

          {

                   if(node_no==insert_no)

                   {

                             new1=(struct link *)malloc(sizeof(struct link));

                             printf("\n Insert data for new node:- ");

                             scanf("%d",&new1->no);

                             node->pre->next=new1;

                             new1->pre=node->pre;

                             new1->next=node;

                             node->pre=new1;

                             flag=1;

                             break;

                   }

                   else

                   {

                             node=node->next;

                   }

                   node_no++;

          }

          if(flag==0)

          {

                   printf("\n Position not found");

          }

}

Posted By : Ruchita Pandya