using System;

using System.Drawing;

using System.Runtime.InteropServices;

namespace RECTvsRectangle

{

    [StructLayout(LayoutKind.Sequential)]

    public struct RECT

    {

        public int Left;

        public int Top;

        public int Right;

        public int Bottom;

    }

    static class Program

    {

        static void Main()

        {

            int intSize = Marshal.SizeOf(typeof(int));

            int rectangleSize = Marshal.SizeOf(typeof(Rectangle));

            int rectSize = Marshal.SizeOf(typeof(RECT));

            RECT r1;

            r1.Left = 1;

            r1.Top = 2;

            r1.Right = 3; //width = 2

            r1.Bottom = 4; //height = 2

            Rectangle r2 = Rectangle.Empty;

            r2.X = 1;

            r2.Y = 2;

            r2.Width = 2;

            r2.Height = 2;

            IntPtr p1 = Marshal.AllocCoTaskMem(rectSize);

            Marshal.StructureToPtr(r1, p1, true);

            IntPtr p2 = Marshal.AllocCoTaskMem(rectangleSize);

            Marshal.StructureToPtr(r2, p2, true);

            for (int i = 0; i < rectSize; i += intSize)

            {

                Console.WriteLine("Value: " + Marshal.ReadInt32(p1, i).ToString());

            }

            Console.WriteLine("---");

            for (int i = 0; i < rectangleSize; i += intSize)

            {

                Console.WriteLine("Value: " + Marshal.ReadInt32(p2, i).ToString());

            }

            Marshal.FreeCoTaskMem(p1);

            Marshal.FreeCoTaskMem(p2);

        }

    }

}