• Skip to primary navigation
  • Skip to content
  • Skip to primary sidebar
  • Skip to secondary sidebar

GoHired

Interview Questions asked in Google, Microsoft, Amazon

Join WeekEnd Online Batch from 4-April-2020 on How to Crack Coding Interview in Just 10 Weeks : Fees just 20,000 INR

  • Home
  • Best Java Books
  • Algorithm
  • Internship
  • Certificates
  • About Us
  • Contact Us
  • Privacy Policy
  • Array
  • Stack
  • Queue
  • LinkedList
  • DP
  • Strings
  • Tree
  • Mathametical
  • Puzzles
  • Graph

Doubly linked list

February 26, 2014 by Dhaval Dave

In computer science, a doubly-linked list is a linked data structure that consists of a set of sequentially linked records called nodes. Each node contains two fields, called links, that are references to the previous and to the next node in the sequence of nodes. The beginning and ending nodes’ previous and next links, respectively, point to some kind of terminator, typically a sentinel node or null, to facilitate traversal of the list. If there is only one sentinel node, then the list is circularly linked via the sentinel node. It can be conceptualized as two singly linked lists formed from the same data items, but in opposite sequential orders.

The two node links allow traversal of the list in either direction. While adding or removing a node in a doubly-linked list requires changing more links than the same operations on a singly linked list, the operations are simpler and potentially more efficient (for nodes other than first nodes) because there is no need to keep track of the previous node during traversal or no need to traverse the list to find the previous node, so that its link can be modified.

#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)
{
    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;
     }
} 

void insert_end(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
     {
         last=head;
         while(last!=NULL)
         {
             temp=last;
             last=last->next;
         }
     last=var;
     temp->next=last;
     last->previous=temp;
     last->next=NULL;
     }
}   

int insert_after(int value, int loc)
{
     struct node *temp,*var,*temp1;
     var=(struct node *)malloc(sizeof(struct node));
     var->data=value;
         if(head==NULL)
     {
           head=var;
           head->previous=NULL;
           head->next=NULL;
     }
     else
     {
           temp=head;
           while(temp!=NULL && temp->data!=loc)
           {
                 temp=temp->next;
           }
           if(temp==NULL)
           {
                printf("n%d is not present in list ",loc);
           }
           else
           {
           temp1=temp->next;
           temp->next=var;
           var->previous=temp; 
          var->next=temp1;
           temp1->previous=var;
           }
     }
     last=head;
     while(last->next!=NULL)
     {
           last=last->next;
     }
}   
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;
} 

int delete_from_middle(int value)
{
    struct node *temp,*var,*t, *temp1;
    temp=head;
    while(temp!=NULL)
    {
        if(temp->data == value)
        {
             if(temp->previous==NULL)
             {
                  free(temp);
                  head=NULL;
                  last=NULL;
                  return 0;
             }
             else
             {
                  var->next=temp1;
                  temp1->previous=var;
                  free(temp);
                  return 0;
             }
        }
        else
        {
              var=temp;
              temp=temp->next;
              temp1=temp->next;
        }
    }
    printf("data deleted from list is %d",value);
}  

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

int main()
{
    int value, i, loc;
    head=NULL;
    printf("Select the choice of operation on link list");
    printf("n1.) insert at begningn2.) insert at atn3.) insert at middle");
    printf("n4.) delete from endn5.) reverse the link listn6.) display listn7.)exit");
    while(1)
    {
          printf("nnenter the choice of operation you want to do ");
          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:
                 {
                 printf("enter the value you want to insert in node at last ");
                 scanf("%d",&value);
                 insert_end(value);
                 display();
                 break;
                 }
                 case 3:
                 {
                 printf("after which data you want to insert data ");
                 scanf("%d",&loc);
                 printf("enter the data you want to insert in list ");
                 scanf("%d",&value);
                 insert_after(value,loc);
                 display();
                 break;
                 }
                 case 4:
                 {
                 delete_from_end();
                 display();
                 break;
                 }
                 case 5:
                 {
                 printf("enter the value you want to delete");
                 scanf("%d",value);
                 delete_from_middle(value);
                 display();
                 break;
                 }
                 case 6 :
                 {
                 display();
                 break;
                 }
                 case 7 :
                 {
                      exit(0);
                      break;
                 }
          }
    }
    printf("nn%d",last->data);
    display();
    getch();
}

 

Similar Articles

Filed Under: problem Tagged With: Linked List

Reader Interactions

Primary Sidebar

Join WeekEnd Online/Offline Batch from 4-April-2020 on How to Crack Coding Interview in Just 10 Weeks : Fees just 20,000 INR

Join WeekEnd Online/Offline Batch from 4-April-2020

WhatsApp us

Secondary Sidebar

Custom Search

  • How I cracked AMAZON
  • LeetCode
  • Adobe
  • Amazon
  • Facebook
  • Microsoft
  • Hacker Earth
  • CSE Interview

Top Rated Questions

Printing each word reverse in string

Memory Efficient LinkedList

Naurki.com Security Breach

BFS (Breath First Search)

Sort Stack in place

How Radix sort works

BlueStone E-commerce Interview Experience

Microsoft BING Interview Experience

Singly linked list

Python String and numbers

N teams are participating. each team plays twice with all other teams. Some of them will go to the semi final. Find Minimum and Maximum number of matches that a team has to win to qualify for finals ?

Rectangular chocolate bar Create at least one piece which consists of exactly nTiles tiles

Closed Parentheses checker

Connect n ropes with minimum cost

Puzzle : 100 doors in a row Visit and Toggle the door. What state the door will be after nth pass ?

CodeChef’ RRCOPY

Leetcode: Merge Intervals

Binary Tree Isomorphic to each other

C Program for TAIL command of UNIX

Number of Islands BFS/DFS

Best Java Book | Top Java Programming Book for Beginners

Facebook Interview Question : Interleave List

Find next greater number with same set of digits

Reverse a Linked List in groups of given size

LeetCode: Binary Tree Maximum Path Sum

Find the smallest window in a string containing all characters of another string

Spanning Tree

write a c program that given a set a of n numbers and another number x determines whether or not there exist two elements in s whose sum is exactly x

Find the number ABCD such that when multipled by 4 gives DCBA.

LeetCode : Word Search

Copyright © 2025 · Genesis Framework · WordPress · Log in