Insert node at beginning of linked list c program

Write a program which is create and add new node at the beginning of linked list in c language.

insert node at beginning of linked list

Here given of code implementation process.

/*
    C program for
    Insert linked list node at beginning of linked list
*/
#include <stdio.h>
#include <stdlib.h>

// Linked List LinkNode
struct LinkNode
{
    int data;
    struct LinkNode *next;
};
// Singly linked list 
struct SingleLL
{
    struct LinkNode *head;
};
// Returns the new linked list
struct SingleLL *newLinkedList()
{
    // Create memory of head and tail Nodes
    struct SingleLL *sll = (struct SingleLL *)
    malloc(sizeof(struct SingleLL));
    if (sll == NULL)
    {
        printf("Memory overflow\n");
    }
    else
    {
        sll->head = NULL;
    }
    return sll;
}
// Handles the request of adding new node at beginning of linked list
void addNode(struct SingleLL *sll, int data)
{
    // Create dynamic node
    struct LinkNode *node = (struct LinkNode *)
    malloc(sizeof(struct LinkNode));
    if (node == NULL)
    {
        printf("Memory overflow to Create LinkNode\n");
        return;
    }
    else
    {
        // Set initial node value
        node->data = data;
        node->next = sll->head;
    }
    sll->head = node;
}
// Display linked list element
void display(struct LinkNode *node)
{
    if (node == NULL)
    {
        return;
    }
    struct LinkNode *temp = node;
    // iterating linked list elements
    while (temp != NULL)
    {
        printf(" %d →", temp->data);
        // Visit to next node
        temp = temp->next;
    }
    printf(" NULL\n");
}
int main(int argc, char const *argv[])
{
    struct SingleLL *sll = newLinkedList();
    // Linked list
    // 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → NULL
    addNode(sll, 8);
    addNode(sll, 7);
    addNode(sll, 6);
    addNode(sll, 5);
    addNode(sll, 4);
    addNode(sll, 3);
    addNode(sll, 2);
    addNode(sll, 1);
    printf(" Linked List \n");
    display(sll->head);
    return 0;
}
Visualize the insert node beginning of singly linked list
 Linked List
 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → NULL

Time complexity of above program is O(1).



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