Adding a node at the beginning of a singly linked list

If you have been learning about Linked Lists, this is the fun and easy part. Adding nodes. Adding nodes means getting to store data in memory.

A node uses the struct construct. Something that looks like this.

/**
 * struct node - node structure
 * @value: integer stored by node
 * @next: pointer to the next node
 * Description: Node is used for a
 * Linked list
 */
typedef struct node
{
        int value;
        struct node *next;
} node;        

See how simple this is. I presume that you have knowledge of structs and pointers.

After defining our node. It is time to use it! So, let us add a node at the beginning of the list and ensure that each time, we a node is added, it goes to the beginning of the list

We shall accomplish this using a function.

void add_node_front(node **head, int value);        

After defining the function. Now let us write it, then call it in the main function.

#include "main.h"
#include <stdio.h>
#include <stdlib.h>
/**
 * add_node_front - adds node to the front of the
 * list
 * @head: pointer to the head node
 * @value: value to be added to the struct
 * Return: void
 */
void add_node_front(node **head, int value)
{
        node *newNode;

        newNode = malloc(sizeof(node));
        if (newNode == NULL)
                printf("Memory Allocation failed\n");
        newNode->value = value;
        newNode->next = *head;
        *head = newNode;
}        

I have used a header file called main.h to store all my functions. Now, here is our main file so that we can call our function.

#include <stdio.h>
#include "main.h"
/**
 * main - example to show how nodes work
 * Return: 0 always success
 */
int main(void)
{
        node *head;

        head = NULL;
        add_node_front(&head, 22);
        add_node_front(&head, 36);
        while (head != NULL)
        {
                printf("Value = %d\n", head->value);
                printf("Current memory location = %p\n",(void *)head);
                printf("Next memory location = %p\n",(void *)head->next);
                head = head->next;
        }
        return (0);
}        

This function adds a node at the beginning of your node. If you want to learn how to add a node at the end of the list, here is an article explaining it with an example. Happy learning.