using System;
using System.Runtime.InteropServices;
 
class Hello
{
     [DllImport("user32.dll", CharSet=CharSet.Auto)]
     private extern static uint MessageBox(IntPtr hWnd, string lpText, string lpCaption, uint uType);
     static void Main(string[] args)
    {
        MessageBox( new IntPtr(0), "Hello, Win32 API(C#) World!", "Hello, World!", 0 );
    }
}