fixed ll test

int main(void) {

    // -> here's a linked list test

    // linked_list_item *first_element = NULL;

    // linked_list_item **head = &first_element;

    //

    // push(head, 2);

    // push(head, 3);

    // push(head, 1);

    //

    // head = &first_element;

    //

    // while ((*head) != NULL) {

    //     printf("value is %d\n", (*head)->value);

    //     head = &(*head)->next;

    // }

    //

    // head = &first_element;

    // delete_linked_list(head);

    //

    // // sanity check: this should print nothing

    linked_list_item *first_element = NULL;

    linked_list_item *curr = first_element;

    push(&curr, 2);

    push(&curr, 3);

    push(&curr, 1);

    // Forward traversal using a separate cursor and also remember tail

    linked_list_item *tail = NULL;

    while (curr != NULL) {

        printf("value is %llu\n", curr->value);

        tail = curr;

        curr = curr->next;

    }

    printf("reverse!\n");

    // Reverse traversal starting from tail using prev pointers

    curr = tail;

    while (curr != NULL) {

        printf("value is %llu\n", curr->value);

        curr = curr->prev;

    }

    // Clean up

    // head = &first_element;

    // while ((*head) != NULL) {

    //     printf("value is %d\n", (*head)->value);

    //     head = &(*head)->next;

    // }

    delete_linked_list(&first_element);

    // sanity check: this should print nothing

    curr = first_element;

    while (curr != NULL) {

        printf("value is %llu\n", curr->value);

        curr = curr->next;

    }

    // -> here's a fibonacci number test

    //      note the inefficiency: with a singly linked list, get_fibonacci_value_at() always works linearly

    //      todo as improvement, keep a doubly linked list & retain current index + value for potentially shorter moves

    for (unsigned int i = 0; i < 100; i++) {

        printf("i %u, fibonacci number: %llu\n", i, get_fibonacci_value_at(i));

    }

    // for (unsigned int i = 0; i < 100; i++) {

    //     printf("i %u, fibonacci number: %llu\n", i, get_fibonacci_value_at(i));

    // }

    return 0;

}