linked list delete program code example

Example: delete function in a singly linked list in c

// A complete working C program
// to demonstrate deletion in
// singly linked list
#include <stdio.h>
#include <stdlib.h>
 
// A linked list node
struct Node {
    int data;
    struct Node* next;
};
 
/* Given a reference (pointer to pointer) to the head of a
   list and an int, inserts a new node on the front of the
   list. */
void push(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;
}
 
/* Given a reference (pointer to pointer) to the head of a
   list and a key, deletes the first occurrence of key in
   linked list */
void deleteNode(struct Node** head_ref, int key)
{
    // Store head node
    struct Node *temp = *head_ref, *prev;
 
    // If head node itself holds the key to be deleted
    if (temp != NULL && temp->data == key) {
        *head_ref = temp->next; // Changed head
        free(temp); // free old head
        return;
    }
 
    // Search for the key to be deleted, keep track of the
    // previous node as we need to change 'prev->next'
    while (temp != NULL && temp->data != key) {
        prev = temp;
        temp = temp->next;
    }
 
    // If key was not present in linked list
    if (temp == NULL)
        return;
 
    // Unlink the node from linked list
    prev->next = temp->next;
 
    free(temp); // Free memory
}
 
// This function prints contents of linked list starting
// from the given node
void printList(struct Node* node)
{
    while (node != NULL) {
        printf(" %d ", node->data);
        node = node->next;
    }
}
 
// Driver code
int main()
{
    /* Start with the empty list */
    struct Node* head = NULL;
 
    push(&head, 7);
    push(&head, 1);
    push(&head, 3);
    push(&head, 2);
 
    puts("Created Linked List: ");
    printList(head);
    deleteNode(&head, 1);
    puts("\nLinked List after Deletion of 1: ");
    printList(head);
    return 0;
}