感心した練習問題の出し方

Let's build cars!

構造体(struct)と列挙型(enum)の練習問題。

Rust初心者の私には良い練習問題だと思ったのと、問題を解くために必要な要求がすべてコードにかかれており、余計な問題文がないことが新鮮だったため、転載します。

struct Car {
    color: String,
    transmission: Transmission,
    convertible: bool,
    mileage: u32,
}

# [derive(PartialEq, Debug)]
enum Transmission {
    Manual,
    SemiAuto,
    Automatic,
}

fn car_factory(color: String, transmission: Transmission, convertible: bool) -> Car {

    // To Do - Fix this part of the function to create a new Car object as requested by the client
    let car: Car = todo!("Replace this with an actual Car instance")

    // Factory's Quality Control Department says that new cars must always have zero mileage!
    assert_eq!(car.mileage, 0);

    // Display the details of the new car order
    if car.convertible {
        println!("New car = {}, {:?}, Convertible", car.color, car.transmission);
    } else {
        println!("New car = {}, {:?}, Hardtop", car.color, car.transmission);
    }

    return car;
}

fn main() {
    let client_request_1 = car_factory(String::from("Red"), Transmission::Manual, false);
    assert_eq!(client_request_1.color, "Red");
    assert_eq!(client_request_1.transmission, Transmission::Manual);
    assert_eq!(client_request_1.convertible, false);

    let client_request_2 = car_factory(String::from("Silver"), Transmission::Automatic, true);
    assert_eq!(client_request_2.color, "Silver");
    assert_eq!(client_request_2.transmission, Transmission::Automatic);
    assert_eq!(client_request_2.convertible, true);

    let client_request_2 = car_factory(String::from("Yellow"), Transmission::SemiAuto, false);
    assert_eq!(client_request_2.color, "Yellow");
    assert_eq!(client_request_2.transmission, Transmission::SemiAuto);
    assert_eq!(client_request_2.convertible, false);
}

正しいコードの出力結果

New car = Red, Manual, Hardtop
New car = Silver, Automatic, Convertible
New car = Yellow, SemiAuto, Hardtop

引用元