// csc demo.cs /out:demo_cs.exe

using System;
using System.Windows.Forms;

namespace Demo
{
    static class Program
    {
        static void Main()
        {
            const string message = "Hello World!";
            const string title = "Demo";
            MessageBox.Show(message, title, MessageBoxButtons.OK);

            Environment.Exit(0);
        }
    }
}
