// ./src/trait/derive.md // `Centimeters`, a tuple struct that can be compared #[derive(PartialEq, PartialOrd)] struct Centimeters(f64); // `Inches`, a tuple struct that can be printed #[derive(Debug)] struct Inches(i32); impl Inches { fn to_centimeters(&self) -> Centimeters { let &Inches(inches) = self; Centimeters(inches as f64 * 2.54) } } // `Seconds`, a tuple struct with no additional attributes struct Seconds(i32); fn part0() { let _one_second = Seconds(1); // Error: `Seconds` can't be printed; it doesn't implement the `Debug` trait //println!("One second looks like: {:?}", _one_second); // TODO ^ Try uncommenting this line // Error: `Seconds` can't be compared; it doesn't implement the `PartialEq` trait //let _this_is_true = (_one_second == _one_second); // TODO ^ Try uncommenting this line let foot = Inches(12); println!("One foot equals {:?}", foot); let meter = Centimeters(100.0); let cmp = if foot.to_centimeters() < meter { "smaller" } else { "bigger" }; println!("One foot is {} than one meter.", cmp); } pub fn main() { part0(); }