ポリモーフィズムをRustでやってみる

polymorphism.rs

// 参考：https://qiita.com/Nossa/items/a93024e653ff939115c6
trait Shape{
    fn area(&self)->f32;
    fn whoami(&self)->String;
}

struct Triangle {
    pub base:f32,
    pub height:f32
}
impl Triangle{
    pub fn new(base:f32,height:f32)->Self{
        Triangle{base:base,height:height}
    }
}
impl Shape for Triangle{
    fn area(&self)->f32{self.base * self.height / 2.0}
    fn whoami(&self)->String{
        format!("I'm Triangle!\nbase: {}  height: {}",self.base,self.height)
    }
}

struct Circle {
    pub radius:f32
}
impl Circle{
    pub fn new(radius:f32)->Self{
        Circle{radius:radius}
    }
}
impl Shape for Circle{
    fn area(&self)->f32{self.radius*self.radius*3.1415926535}
    fn whoami(&self)->String{
        format!("I'm Circle!\nradius: {}",self.radius)
    }
}

struct Rectangle {
    pub width:f32,
    pub height:f32
}

impl Rectangle{
    pub fn new(width:f32,height:f32)->Self{
        Rectangle{width:width,height:height}
    }
}
impl Shape for Rectangle{
    fn area(&self)->f32{self.width*self.height}
    fn whoami(&self)->String{
        format!("I'm Rectangle!\nwidth: {}  height: {}",self.width,self.height)
    }
}

fn main(){
    for o in &[Box::new(Rectangle::new(10.0,20.0)) as Box<Shape>,
                    Box::new(Triangle::new(10.0,20.0)) as Box<Shape>,
                    Box::new(Circle::new(30.0)) as Box<Shape>]{
        println!("{}",o.whoami());
        println!("area : {}\n",o.area());
    }
}