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

C++Server Side ProgrammingProgramming

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

Let's see the steps to solve the problem.

  • Write struct with data, and next pointer.

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

  • Initialize the singly 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 *next;
};
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->next = (*head_ref);
   (*head_ref) = new_node;
}
void deleteNode(struct Node **head_ref, int position) {
   if (*head_ref == NULL) {
      return;
   }
   struct Node* temp = *head_ref;
   if (position == 1) {
      *head_ref = temp->next;
      free(temp);
      return;
   }
   for (int i = 2; temp != NULL && i < position - 1; i++) {
      temp = temp->next;
   }
   if (temp == NULL || temp->next == NULL) {
      return;
   }
   struct Node *next = temp->next->next;
   free(temp->next);
   temp->next = next;
}
void printLinkedList(struct Node *node) {
   while (node != NULL) {
      cout << node->data << "->";
      node = node->next;
   }
}
int main() {
   struct 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, 1);
   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:
4->3->2->1->

Conclusion

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

raja
Published on 30-Dec-2020 11:11:02
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