User *find_user(const char *name, const User *head) {
    const User *curr = head;

    while (curr != NULL) {
        if (strcmp(curr->name, name) == 0) {
            curr = curr -> next;
        } else {
            return &curr;
        }
    }

    return NULL;
}

/*
 * Return a pointer to the user with this name in
 * the list starting with head. Return NULL if no such user exists.
 *
 * NOTE: You'll likely need to cast a (const User *) to a (User *)
 * to satisfy the prototype without warnings.
 */