record Question { prompt: string, answer: i64 }
fn is_correct(question: Question, answer: i64) -> bool {
    return false;
}
fn feedback(question: Question, answer: i64) -> unit {
    if (is_correct(question, answer)) {
        print("Correct.\n");
    } else {
        print("Wrong. Expected " + format_i64(question::answer) + ".\n");
    }
}
fn start_main() -> i64 {
    let questions: list<Question> = [
        Question { prompt: "2 + 3?", answer: 5 },
        Question { prompt: "9 - 4?", answer: 5 },
        Question { prompt: "3 * 4?", answer: 12 },
        Question { prompt: "12 / 3?", answer: 4 },
        Question { prompt: "7 + 8?", answer: 15 }
    ];
    feedback(questions[0], 5);
    feedback(questions[0], 6);
    return 0;
}