Delete a node in a Doubly Linked List in C++

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

Approach

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.

• Take a node to delete.

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

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

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

  • If the node is the end node, then remove the previous node link. Let's see the code.

Example

Here is the following example of deleting a node in a doubly linked list in C++.

#include <bits/stdc++.h>
using namespace std;
struct Node {
 int data;
 Node *prev, *next;
};
void deleteNode(Node** head_ref, Node* del) {
 if (*head_ref == NULL || del == NULL) {
return;
 }
 if (*head_ref == del) {
*head_ref = del->next;
 }
 if (del->next != NULL) {
del->next->prev = del->prev;
 }
 if (del->prev != NULL) {
del->prev->next = del->next;
 }
 free(del);
 return;
}
void insertNode(Node** head_ref, int new_data) {
 Node* new_node = new 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(Node* node) {
 while (node != NULL) {
cout << node->data << " -> ";
node = node->next;
 }
}
int main() {
 Node* head = NULL;
 insertNode(&head, 1);
 insertNode(&head, 2);
 insertNode(&head, 3);
 insertNode(&head, 4);
 insertNode(&head, 5);
 cout << "Linked List before deletion:" << endl;
 printLinkedList(head);
 deleteNode(&head, head->next);
 cout << "\nLinked List after deletion:" << endl;
 printLinkedList(head);
 return 0;
}

Output

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

Linked List before deletion:
5 -> 4 -> 3 -> 2 -> 1 ->
Linked List after deletion:
5 -> 3 -> 2 -> 1 ->

Conclusion

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