traists_has_area.rs

trait HasArea {
    fn area(&self) -> f64;
}


struct Cyrcle {
    radius : f64,
}

impl HasArea for Cyrcle {
    fn area(&self) -> f64 {
        std::f64::consts::PI * self.radius.powi(2)
    }
}


struct Square {
    a : f64,
}

impl HasArea for Square {
    fn area(&self) -> f64 {
        self.a.powi(2)
    }
}

struct Rectangle {
    a : f64,
    b : f64,
}

impl HasArea for Rectangle {
    fn area(&self) -> f64 {
        self.a * self.b
    }
}


fn print_area<T : HasArea>(shape : &T) {
    println!("Shape: {}", shape.area());
}


fn main() {
    let cyrcle = Cyrcle { radius: 10.0 };
    let square = Square { a: 5.0 };
    let rectangle = Rectangle { a: 4.0, b: 10.0 };

    print_area(&cyrcle);
    print_area(&square);
    print_area(&rectangle);
}