Delete a Doubly Linked List node at a given position in C++

In this tutorial, we are going to learn how to delete a node in doubly linked list with the given position.

Let's see the steps to solve the problem.

• Write struct with data, prev and next pointers.

• Write a function to insert the node into the doubly linked list.

• Initialize the doubly linked list with dummy data.

• Initialize the position to delete the node.

• Iterate over the linked list and find the node with the given position to delete the node.

• Write a function to delete the node. Consider the following three cases while deleting the node.

  • If the node is head node, then move the head to next node.

  • If the node is middle node, then link the next node to the previous node

  • If the node is end node, then remove the previous node link.

Example

Let's see the code.

 Live Demo

#include <bits/stdc++.h> using namespace std; struct Node {    int data;    struct Node *prev, *next; }; void deleteNode(struct Node** head_ref, struct Node* del) {    if (*head_ref == NULL || del == NULL) {       return;    }    // head node    if (*head_ref == del) {       *head_ref = del->next;    }    // middle node    if (del->next != NULL) {       del->next->prev = del->prev;    }    // end node    if (del->prev != NULL) {       del->prev->next = del->next;    }    free(del); } void deleteNodeAtGivenPosition(struct Node** head_ref, int n) {    if (*head_ref == NULL || n <= 0) {       return;    }    struct Node* current = *head_ref;    int i;    for (int i = 1; current != NULL && i < n; i++) {       current = current->next;    }    if (current == NULL) {       return;    }    deleteNode(head_ref, current); } void insertNode(struct Node** head_ref, int new_data) {    struct Node* new_node = (struct Node*)malloc(sizeof(struct Node));    new_node->data = new_data;    new_node->prev = NULL;    new_node->next = (*head_ref);    if ((*head_ref) != NULL) {       (*head_ref)->prev = new_node;    }    (*head_ref) = new_node; } void printLinkedList(struct Node* head) {    while (head != NULL) {       cout << head->data << "->";       head = head->next;    } } int main() {    struct Node* head = NULL;    insertNode(&head, 5);    insertNode(&head, 2);    insertNode(&head, 4);    insertNode(&head, 8);    insertNode(&head, 10);    cout << "Doubly linked list before deletion" << endl;    printLinkedList(head);    int n = 2;    deleteNodeAtGivenPosition(&head, n);    cout << "\nDoubly linked list after deletion" << endl;    printLinkedList(head);    return 0; }

Output

If you execute the above program, then you will get the following result.

Doubly linked list before deletion 10->8->4->2->5-> Doubly linked list after deletion 10->4->2->5->

Conclusion

If you have any queries in the tutorial, mention them in the comment section.