结构体和方法

 

use std::fmt;#[derive(Debug)]struct Rectangle {    width: u32,    height: u32,}impl std::fmt::Display for Rectangle {    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {        write!(f, "Rectangle width: {} height: {}", self.width, self.height)    }}impl Rectangle {    fn area(&self) -> u32 {        self.width * self.width    }    fn can_hold(&self, other: &Rectangle) -> bool {        self.width > other.width && self.height > other.height    }    fn square(size: u32) -> Rectangle {        Rectangle {            width: size,            height: size,        }    }}fn main() {    let rect1 = Rectangle { width: 30, height: 50 };    let rect2 = Rectangle { width: 10, height: 40 };    let rect3 = Rectangle { width: 60, height: 45 };    let rect4 = Rectangle::square(40);    println!("Can rect1 hold rect2? {}", rect1.can_hold(&rect2));    println!("Can rect1 hold rect3? {}", rect1.can_hold(&rect3));    println!("rect4 is {}", rect4);    println!("rect4 is {:#?}", rect4);    println!(        "The area of the rectangle is {} square pixels.",        rect4.area()    );}