// Pantea Aria
// linked list introduction

// What is a linked list? How is it different from an array? static memory 
// collection of same data type - dynamic memory in linked list malloc 

// Draw a linked list of three nodes with values 10, 20, and 30.

// What does the last node of a singly linked list point to? NULL

// make linked lists with 3 nodes, print each node's data
    
#include <stdio.h>
#include <stdlib.h>

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

int main (void) {

    // declare, malloc and initialise for first node
    struct node *first = malloc(sizeof(struct node));
    // always check if it is not returning NULL your turn
    first->data = 10;
    first->next = NULL;
    // declare, malloc and initialise for second node
    struct node *second = malloc(sizeof(struct node));
        // always check if it is not returning NULL your turn
    second->data = 20;
    second->next = NULL;    
    // declare, malloc and initialise for third node
    struct node *third = malloc(sizeof(struct node));
    // always check if it is not returning NULL your turn
    third->data = 30;
    third->next = NULL;
    // link first to second
    // I must update the first node's next
    first->next = second;
    // link second to third
    // I must update the next of second node
    second->next = third;
  
    // print out all values using first node
    printf("%d %d %d\n", first->data, 
        first->next->data, 
        first->next->next->data);
    
    
    // print all next
    printf("%p %p %p\n", first, first->next, first->next->next);
    printf("%p %p %p\n", first, second, third);

    free(first);
    free(second);
    free(third);
    return 0;
}