Rust MulAssign用法及代碼示例

use std::ops::MulAssign;

#[derive(Debug, PartialEq)]
struct Frequency { hertz: f64 }

impl MulAssign<f64> for Frequency {
    fn mul_assign(&mut self, rhs: f64) {
        self.hertz *= rhs;
    }
}

let mut frequency = Frequency { hertz: 50.0 };
frequency *= 4.0;
assert_eq!(Frequency { hertz: 200.0 }, frequency);