insertion at end.c

// INSERTION AT END PROGRAM

#include <stdio.h>
#include <stdlib.h>

struct node
{
    int data;
    struct node *next;
};

void addLast(struct node **head, int val)
{
    // create a new node
    struct node *newNode = malloc(sizeof(struct node));
    newNode->data = val;
    newNode->next = NULL;

    // if head is NULL, it is an empty list
    if (*head == NULL)
        *head = newNode;
    // Otherwise, find the last node and add the newNode
    else
    {
        struct node *lastNode = *head;

        // last node's next address will be NULL.
        while (lastNode->next != NULL)
        {
            lastNode = lastNode->next;
        }

        // add the newNode at the end of the linked list
        lastNode->next = newNode;
    }
}

void printList(struct node *head)
{
    struct node *temp = head;

    // iterate the entire linked list and print the data
    while (temp != NULL)
    {
        printf("%d->", temp->data);
        temp = temp->next;
    }
    printf("NULL\n");
}

int main()
{
    struct node *head = NULL;

    addLast(&head, 10);
    addLast(&head, 20);
    addLast(&head, 30);

    printList(head);

    return 0;
}