int make_post(const User *author, User *target, char *contents) {

    if (author == NULL || target == NULL) {
        return 2;
    }
    bool is_friends = false;
    for (int i = 0; i < MAX_FRIENDS; i++) {
        if (target->friends[i] == author) {
            is_friends = true;
            break;
        }
    }

    if (!is_friends) {
        return 1;
    }

    Post *new_post = (Post *)malloc(sizeof(Post));
    strcpy(new_post->author, author->name);
    new_post->contents = contents;
    new_post->date = (time_t *)malloc(sizeof(time_t));
    time(new_post->date);

    new_post->next = target->first_post;
    target->first_post = new_post;

    return 0;
}

/*
 * Make a new post from 'author' to the 'target' user,
 * containing the given contents, IF the users are friends.
 *
 * Insert the new post at the *front* of the user's list of posts.
 *
 * 'contents' is a pointer to heap-allocated memory - you do not need
 * to allocate more memory to store the contents of the post.
 *
 * Return:
 *   - 0 on success
 *   - 1 if users exist but are not friends
 *   - 2 if either User pointer is NULL
 */