环境

• Rust 1.55.0
• VSCode 1.59.1

概念

参考：https://doc.rust-lang.org/stable/rust-by-example/custom_types/structs.html

Add a function square which takes a Point and a f32 as arguments, and returns a Rectangle with its lower left corner on the point, and a width and height corresponding to the f32.

增加一个函数 square，接受的参数是一个 Point 和一个 f32，并返回一个 Rectangle（长方形），其左下角的点等于 Point 参数，长和宽都等于 f32 参数。

示例

#[derive(Debug)]
struct Point {
    x: f32,
    y: f32,
}

#[derive(Debug)]
struct Rectangle {
    top_left: Point,
    bottom_right: Point,
}

fn square(point: &Point, length: f32) -> Rectangle {
    Rectangle {
        top_left: Point {
            x: point.x,
            y: point.y + length,
        },
        bottom_right: Point {
            x: point.x + length,
            y: point.y,
        },
    }
}

fn main() {
    println!("square: {:?}", square(&Point { x: 0.0, y: 0.0 }, 1.0));
}

总结

根据要求，实现生成长方形的方法。

附录