C Program for Deletion from nth position in doubly linked list

March 19, 2025

Deletion from particular position in doubly linked list

In this article we will learn C Program for Deletion from nth position in doubly linked list, the task is to delete the specific node by the user input.Here we have given algorithm ,working and code to understand better .
For Example :-
Input : 61   4   77   10   32
Enter the position from where you want to delete node : 3
Output : 61   4   10   32

C Program for Deletion from nth position in doubly linked list

Working needed for deleting node from the nth node in the doubly linked list :-

  • Make a new doubly linked list.
  • Then copy the address of head pointer into a temporary pointer .
  • Traverse the linked list until we find the desired position.
  • After that we have to make the next pointer of this node point to null so that it can be the new last node of the list.

How to made node Structure in the doubly linked list

struct node   
{  
    struct node *prev;   
    int data;  
    struct node *next;   
}
Deletion in Doubly Linked List in C 1

Singly Linked List in C

Deletion in singly Linked List

Doubly Linked List in C

Insertion in the middle in a doubly linked list

Circular Linked List in C

Algorithm require for deleting node from the specific position in the linked list

  • IF HEAD = NULL (GOTO STEP 9 AND END OF IF LOOP)
  • NOW ASSIGN EXTRA = HEAD
  • REPEAT STEP 4 WHILE TEMP → DATA != VALUE
  • ASSIGN EXTRA = EXTRA → NEXT
  • ASSIGN POINTER = EXTRA → NEXT
  • ASSIGN EXTRA → NEXT = POINTER → NEXT
  • ASSIGN POINTER → NEXT → PREVIOUS = EXTRA
  • REMOVE POINTER
  • EXIT

Code for Deletion from nth position in a Doubly Linked List

Run 
#include<stdio.h>
#include<stdlib.h>

struct Node
{
  int data;
  struct Node *next;
  struct Node *prev;
};

int getLength (struct Node *node);

void insert (struct Node **head, int data)
{

  struct Node *freshNode = (struct Node *) malloc (sizeof (struct Node));

  freshNode->data = data;
  freshNode->next = *head;
  freshNode->prev = NULL;

  // If the linked list already had atleast 1 node
  if (*head != NULL)
    (*head)->prev = freshNode;

  // freshNode will become head
  *head = freshNode;
}

void deleteFront (struct Node **head)
{
  struct Node *tempNode = *head;

  // if DLL is empty
  if (*head == NULL)
    {
      printf ("Linked List Empty, nothing to delete\n");
      return;
    }

  // if Linked List has only 1 node
  if (tempNode->next == NULL)
    {
      printf ("%d deleted\n", tempNode->data);
      *head = NULL;
      return;
    }

  // move head to next node
  *head = (*head)->next;
  // assign head node's previous to NULL
  (*head)->prev = NULL;

  printf ("%d deleted\n", tempNode->data);
  free (tempNode);
}

void deleteEnd (struct Node **head)
{
  struct Node *tempNode = *head;

  // if DLL is empty
  if (*head == NULL)
    {
      printf ("Linked List Empty, nothing to delete\n");
      return;
    }

  // if Linked List has only 1 node
  if (tempNode->next == NULL)
    {
      printf ("%d deleted\n", tempNode->data);
      *head = NULL;
      return;
    }

  // else traverse to the last node
  while (tempNode->next != NULL)
    tempNode = tempNode->next;

  struct Node *secondLast = tempNode->prev;

  // Curr assign 2nd last node's next to Null
  secondLast->next = NULL;

  printf ("%d deleted\n", tempNode->data);
  free (tempNode);
}

void deleteNthNode (struct Node **head, int n)
{
  //if the head node itself needs to be deleted
  int len = getLength (*head);

  // not valid
  if (n < 1 || n > len)
    {
      printf ("Enter valid position\n");
      return;
    }

  // delete the first node
  if (n == 1)
    {
      deleteFront (head);
      return;
    }

  if (n == len)
    {
      deleteEnd (head);
      return;
    }

  struct Node *tempNode = *head;

  // traverse to the nth node
  while (--n)
    {
      tempNode = tempNode->next;
    }

  struct Node *previousNode = tempNode->prev;	// (n-1)th node
  struct Node *nextNode = tempNode->next;	// (n+1)th node

  // assigning (n-1)th node's next pointer to (n+1)th node
  previousNode->next = tempNode->next;

  // assigning (n+1)th node's previous pointer to (n-1)th node
  nextNode->prev = tempNode->prev;

  // deleting nth node
  printf ("%d deleted \n\n", tempNode->data);
  free (tempNode);
}

// required for deleteNthNode
int
getLength (struct Node *node)
{
  int len = 0;


  while (node != NULL)
    {
      node = node->next;
      len++;
    }

  return len;
}

//function to print the doubly linked list
void display (struct Node *node)
{
  struct Node *end = NULL;

  while (node != NULL)
    {
      printf (" %d ", node->data);
      end = node;
      node = node->next;
    }

  printf ("\n\n");
}

int
main ()
{
  struct Node *head = NULL;

  insert (&head, 7);
  insert (&head, 8);
  insert (&head, 9);
  insert (&head, 10);
  insert (&head, 11);
  insert (&head, 12);

  printf ("Linked List Before Deletion");
  display (head);

  // delete 3rd node

  deleteNthNode (&head, 3);
  printf ("Linked List After Deletion");
  display (head);

  return 0;
}

Output

Linked List Before Deletion 12  11  10  9  8  7

10 deleted 

Linked List After Deletion 12  11  9  8  7