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

typedef struct _Node { // canonical name struct _Node
    int value;
    struct _Node* next; // need to use canonical name
// invalid: Node* next;
/*
linked_list.c:8:2: error: unknown type name ‘Node’
  Node* next;
  ^~~~
*/
} Node; // shortcut name: Node

void print_linked_list(Node* head) {
    // loop to iterate the linked list
    // we could write this as a while loop
    // per CQ, its better to write as a for loop
    for (Node* cur = head; cur != NULL; cur = cur->next) {
        printf("[%d]", cur->value);
        printf("%s", cur->next == NULL ? "\n" : "->");
    }
}

int main(int argc, char* argv[]) {
    // linked list of size 0
    // NULL
    Node* head = NULL;
    Node* tail = NULL;
    print_linked_list(head);

    // linked list of size 1
    // [5]->NULL
    Node* new_node = malloc(sizeof(*new_node));
    *new_node = (Node) { .value = 5, .next = NULL };
    // size 0 to 1: replace both head and tail (were NULL before)
    head = new_node;
    tail = new_node;
    print_linked_list(head);

    // linked list of size 2
    // [5]->[7]->NULL
    new_node = malloc(sizeof(*new_node));
    *new_node = (Node) { .value = 7, .next = NULL };
    // size N to N+1: add new node to the end of tail
    tail->next = new_node;
    // make new node the new tail
    tail = new_node;
    // head will never change once first set unless we remove nodes
    // tail changes every time we append a node
    print_linked_list(head);

    // linked list of size 3
    // [5]->[7]->[9]->NULL
    new_node = malloc(sizeof(*new_node));
    *new_node = (Node) { .value = 9, .next = NULL };
    // size N to N+1: add new node to the end of tail
    tail->next = new_node;
    // make new node the new tail
    tail = new_node;
    print_linked_list(head);

    // linked list of size 4
    // [5]->[7]->[9]->[1]->NULL
    new_node = malloc(sizeof(*new_node));
    *new_node = (Node) { .value = 1, .next = NULL };
    // size N to N+1: add new node to the end of tail
    tail->next = new_node;
    // make new node the new tail
    tail = new_node;
    print_linked_list(head);

    // a later node in a linked list is a valid linked list
    print_linked_list(head->next);

    // TODO: need to free the linked list

    return EXIT_SUCCESS;
}
/* vim: set tabstop=4 shiftwidth=4 fileencoding=utf-8 noexpandtab: */