Activity seems misleading on Custom Types -Structures

[matthewharwood]

Activity
Add a function rect_area which calculates the area of a rectangle (try using nested destructuring).

https://github.com/rust-lang/rust-by-example/blob/master/src/custom_types/structs.md

Given the example, I'm not too sure how we should be calculating the area or the rectangle.

I've made an abridged version of the question/answer:

use std::fmt::{self, Formatter, Display};

struct Point {
    x: f32,
    y: f32,
}

struct Rectangle {
    p1: Point,
    p2: Point,
}

impl Display for Point {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        write!(f, "x: {}, y:{}", self.x, self.y)
    }
    
}
impl Display for Rectangle {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        write!(f, "(p1: {}, p2: {})", self.p1, self.p2)
    }
    
}

 fn rect_area(rect: Rectangle) -> f32 {
    // Is this what you were looking for? seems misleading if so
    // (rect.p1.x - rect.p2.x)*(rect.p1.y - rect.p2.y)
 }
fn main() {
    let point: Point = Point { x: 0.3, y: 0.4 };
    let Point { x: my_x, y: my_y } = point;

    let _rectangle = Rectangle {
        p1: Point { x: my_y, y: my_x },
        p2: point,
    };

    println!("{}", _rectangle);
   //println!("{}", rect_area(_rectangle));
}