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Tuesday, 12 May 2015

Double Linked List Program

This is a program to show how double linked list works.

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
 
struct node
{
     struct node *previous;
     int data;
     struct node *next;
}*head, *last; 

void insert_begning(int value);
int delete_from_end();
void display();

int main()
{
    int value, i, loc;
    head=NULL;
    printf("Select the choice of operation on link list");
    printf("\n1.) insert at begning\n2.)delete from end \n3.) display\n4.exit\n");

    while(1)
    {
          printf("\n\nenter the choice\n");
          scanf("%d",&i);
          switch(i)
          {
            case 1:
                {
                 printf("enter the value you want to insert in node ");
                 scanf("%d",&value);
                 insert_begning(value);
                 display();
                 break;
                }
            case 2:
                   delete_from_end();
                   display();
                   break;
            case 3 :
                   display();
                   break;
            case 4 :
                 {
                      exit(0);
                      break;
                 }
          }
    }
    printf("\n\n%d",last->data);
    display();
    getch();
}

void insert_begning(int value)
{
    struct node *var,*temp;
     var=(struct node *)malloc(sizeof(struct node));
     var->data=value;
     if(head==NULL)
     {
         head=var;
         head->previous=NULL;
         head->next=NULL;
         last=head;
     }
     else
     {
         temp=var;
         temp->previous=NULL;
         temp->next=head;
         head->previous=temp;
         head=temp;
     }
} 

int delete_from_end()
{
      struct node *temp;
      temp=last;
      if(temp->previous==NULL)
      {
           free(temp);
           head=NULL;
           last=NULL;
           return 0;
      }
      printf("\nData deleted from list is %d \n",last->data);
      last=temp->previous;
      last->next=NULL;
      free(temp);
      return 0;
} 

void display()
{
     struct node *temp;
     temp=head;
     if(temp==NULL)
      {
         printf("List is Empty");
      }
     while(temp!=NULL)
     {
          printf("-> %d ",temp->data);
          temp=temp->next;
     }
} 

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