MĂ©todos

Métodos são funçÔes associadas a um tipo específico. O primeiro argumento (self) de um método é uma instùncia do tipo ao qual estå associado:

struct Rectangle {
    width: u32,
    height: u32,
}

impl Rectangle {
    fn area(&self) -> u32 {
        self.width * self.height
    }

    fn inc_width(&mut self, delta: u32) {
        self.width += delta;
    }
}

fn main() {
    let mut rect = Rectangle { width: 10, height: 5 };
    println!("area antiga: {}", rect.area());
    rect.inc_width(5);
    println!("nova area: {}", rect.area());
}
  • Veremos muito mais sobre mĂ©todos no exercĂ­cio de hoje e na aula de amanhĂŁ.

  • Add a static method called Rectangle::new and call this from main:

    fn new(width: u32, height: u32) -> Rectangle {
    Rectangle { width, height }
}

  • While technically, Rust does not have custom constructors, static methods are commonly used to initialize structs (but don’t have to). The actual constructor, Rectangle { width, height }, could be called directly. See the Rustnomicon.

  • Add a Rectangle::square(width: u32) constructor to illustrate that such static methods can take arbitrary parameters.