struct Nil;

struct Pair(i32, f32);

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

#[derive(Debug)]
struct Rectangle {
    p1: Point,
    p2: Point,
}

fn rect_area(rect: Rectangle) -> f32 {
    let Rectangle {
        p1: Point { x: x1, y: y1 },
        p2: Point { x: x2, y: y2 }
    } = rect;
    ((x1 - x2) * (y1 - y2)).abs()
}

fn square(point: Point, dim: f32) -> Rectangle {
    Rectangle {
        p1: Point { x: point.x, y: point.y },
        p2: Point { x: point.x + dim, y: point.y + dim },
    }
}

fn main() {
    let point: Point = Point { x: 0.3, y: 0.4 };

    println!("point coordinates: ({}, {})", point.x, point.y);

    let Point { x: my_x, y: my_y } = point;

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

    let _nil = Nil;

    let pair = Pair(1, 0.1);

    println!("pair contains {:?} and {:?}", pair.0, pair.1);

    let Pair(integer, decimal) = pair;

    println!("pair contains {:?} and {:?}", integer, decimal);

    println!("rect is {:?}", _rectangle);
    println!("rect area is {}", rect_area(_rectangle));

    let dim = 9.1f32;

    println!("point is {:?}", point);
    println!("dim is {:?}", dim);
    let sq = square(point, dim);
    println!("square is {:?}", sq);
    println!("square area is {}", rect_area(sq));
}