// using InteropServices
// the necessary WinApi functions are in kernel32.dll
// in C# Handle = IntPtr  DWORD = uint   WORD = int
// just a console program compiled with:
// C:\Windows\Microsoft.NET\Framework\v2.0.50727\csc.exe
 
using System;
using System.Runtime.InteropServices;  // DllImport()
 
class Class1
{
  // WinApi Beep() is in kernel32.dll  
  [DllImport("kernel32")]
  private static extern int Beep(int dwFreq, int dwDuration);
 
  static void Main(string[] args)
  {
    Console.WriteLine("It's spring time so let's beep!!!!\n\n");
 
    int freq = 440;      // hertz
    int duration = 2000;  // milliseconds
    Console.WriteLine("Beeping at " + freq + " Hz for " + duration + " milliseconds");
    Beep(freq, duration);
  }
}