using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

namespace DefaultNamespace
{
 /// <summary>
 /// Description of Class1. 
 /// </summary>
 public class UdpEchoClient
 {
  private static readonly int BUF_SIZE=2048;
  
  public static void Main(){
   Socket clientSocket=new Socket(AddressFamily.InterNetwork,
                                  SocketType.Dgram,
                                  ProtocolType.Udp
                                  );
   clientSocket.SetSocketOption(SocketOptionLevel.Socket,
                                 SocketOptionName.ReceiveTimeout,
                                 3000
                                 );
   EndPoint serverEndPoint=new IPEndPoint(IPAddress.Parse("127.0.0.1"),
                                          8004
                                          );
   Console.WriteLine("echo client start");
   while(true){
    string input=Console.ReadLine();
    if("exit"==input.ToLower()){
     clientSocket.Close();
     Console.WriteLine("echo client stop.");
     break;
    }
    byte[] buf=Encoding.ASCII.GetBytes(input);
    clientSocket.SendTo(buf,SocketFlags.None,serverEndPoint);
    buf=new byte[BUF_SIZE];
    EndPoint remoteEndPoint=new IPEndPoint(IPAddress.Any,0);
    try{
     int receive=clientSocket.ReceiveFrom(buf,ref remoteEndPoint);
     string strReceive=Encoding.ASCII.GetString(buf,0,receive);
     Console.WriteLine("echoed from server: {0} message:{1}",remoteEndPoint,strReceive);
    }catch(SocketException e){
     Console.WriteLine(e.Message);
    }
   }//while
  }
 }
}