using System;

​

var rect = new Rectangle {

    size = new() { width = 10, height = 10 },

    point = new() { top = 5, left = 5 }

};

Console.WriteLine(rect.size.width);

​

​

struct Size {

    public int width, height;

}

​

struct Point {

    public int top, left;

}

​

struct Rectangle {

    public Size size;

    public Point point;

}