Struct duplicate

This seems to be an old example showing that if we don't compose one struct from another then we have to implement everything in both cases.
In this case the Circle struct has its own x and y attribute and its own mv method.

examples/struct/circle-duplicate/src/main.rs

struct Point {
    x: i32,
    y: i32,
}

struct Circle {
    x: i32,
    y: i32,
    radius: i32,
}

impl Point {
    fn mv(&mut self, dx: i32, dy: i32) {
        self.x += dx;
        self.y += dy;
    }
}

impl Circle {
    fn mv(&mut self, dx: i32, dy: i32) {
        self.x += dx;
        self.y += dy;
    }
    fn area(&self) -> f32 {
        (self.radius as f32) * (self.radius as f32) * (std::f64::consts::PI as f32)
    }
}


fn main() {
    let mut p = Point {x: 2, y: 3};
    println!("{}", p.x);
    println!("{}", p.y);
    println!();

    p.mv(4, 5);
    println!("{}", p.x);
    println!("{}", p.y);
    println!("----");

    let mut a = Circle {x: 2, y: 3, radius: 7};
    println!("{}", a.x);
    println!("{}", a.y);
    println!("{}", a.radius);
    println!("{}", a.area());
    println!();

    a.mv(4, 5);
    println!("{}", a.x);
    println!("{}", a.y);
    println!("{}", a.radius);
}