Los métodos son funciones asociadas a un tipo. El argumento self de un método es una instancia del tipo al que está asociado:
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!("old area: {}", rect.area());
rect.inc_width(5);
println!("new area: {}", rect.area());
}
$ cargo run
Compiling hello_cargo v0.1.0
Finished dev [unoptimized + debuginfo] target(s) in 0.28s
Running `target/debug/hello_cargo`
old area: 50
new area: 75
Podemos definir un constructor :
struct Rectangle {
width: u32,
height: u32,
}
impl Rectangle {
fn new(width: u32, height: u32) -> Rectangle {
Rectangle { width, height }
}
fn area(&self) -> u32 {
self.width * self.height
}
fn inc_width(&mut self, delta: u32) {
self.width += delta;
}
}
fn main() {
let mut rect = Rectangle::new(10, 5);
println!("old area: {}", rect.area());
rect.inc_width(5);
println!("new area: {}", rect.area());
}
