rustlings/solutions/quizzes/quiz1.rs

// Mary is buying apples. The price of an apple is calculated as follows:
// - An apple costs 2 rustbucks.
// - However, if Mary buys more than 40 apples, the price of each apple in the
// entire order is reduced to only 1 rustbuck!

fn calculate_price_of_apples(n_apples: u64) -> u64 {
    if n_apples > 40 {
        n_apples
    } else {
        2 * n_apples
    }
}

fn main() {
    // You can optionally experiment here.
}

// Don't change the tests!
#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn verify_test() {
        assert_eq!(calculate_price_of_apples(35), 70);
        assert_eq!(calculate_price_of_apples(40), 80);
        assert_eq!(calculate_price_of_apples(41), 41);
        assert_eq!(calculate_price_of_apples(65), 65);
    }
}