Imports System
Imports System.IO
Imports System.Net
Imports System.Net.Sockets
Imports System.Text
Imports Microsoft.VisualBasic


Class MyTcpListener

    Public Shared Sub Main()

    Dim server As TcpListener
    server=nothing
        Try
            ' Set the TcpListener on port 13000.
         Dim port As Int32 = 13000
         Dim localAddr As IPAddress = IPAddress.Parse("127.0.0.1")

         server = New TcpListener(localAddr, port)
         
         ' Start listening for client requests.
         server.Start()
         
         ' Buffer for reading data
            Dim bytes(1024) As Byte
            Dim data As String = Nothing
         
         ' Enter the listening loop.
         While True
            Console.Write("Waiting for a connection... ")
            
            ' Perform a blocking call to accept requests.
            ' You could also user server.AcceptSocket() here.
            Dim client As TcpClient = server.AcceptTcpClient()
            Console.WriteLine("Connected!")
            
            data = Nothing
            
            ' Get a stream object for reading and writing
            Dim stream As NetworkStream = client.GetStream()
            
            Dim i As Int32
            
            ' Loop to receive all the data sent by the client.
            i = stream.Read(bytes, 0, bytes.Length)
            While (i <> 0) 
               ' Translate data bytes to a ASCII string.
               data = System.Text.Encoding.ASCII.GetString(bytes, 0, i)
                    Console.WriteLine("Received: {0}", data)
               
               ' Process the data sent by the client.
               data = data.ToUpper()
                    Dim msg As Byte() = System.Text.Encoding.ASCII.GetBytes(data)
               
               ' Send back a response.
               stream.Write(msg, 0, msg.Length)
                    Console.WriteLine("Sent: {0}", data)
              
               i = stream.Read(bytes, 0, bytes.Length)

            End While
            
            ' Shutdown and end connection
            client.Close()
         End While
      Catch e As SocketException
         Console.WriteLine("SocketException: {0}", e)
      Finally
         server.Stop()
      End Try
      
      Console.WriteLine(ControlChars.Cr + "Hit enter to continue....")
      Console.Read()
   End Sub 'Main

End Class 'MyTcpListener 

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

class MyTcpListener
{
  public static void Main()
  { 
    TcpListener server=null;   
    try
    {
      // Set the TcpListener on port 13000.
      Int32 port = 13000;
      IPAddress localAddr = IPAddress.Parse("127.0.0.1");
      
      // TcpListener server = new TcpListener(port);
      server = new TcpListener(localAddr, port);

      // Start listening for client requests.
      server.Start();
         
      // Buffer for reading data
      Byte[] bytes = new Byte[256];
      String data = null;

      // Enter the listening loop.
      while(true) 
      {
        Console.Write("Waiting for a connection... ");
        
        // Perform a blocking call to accept requests.
        // You could also user server.AcceptSocket() here.
        TcpClient client = server.AcceptTcpClient();            
        Console.WriteLine("Connected!");

        data = null;

        // Get a stream object for reading and writing
        NetworkStream stream = client.GetStream();

        int i;

        // Loop to receive all the data sent by the client.
        while((i = stream.Read(bytes, 0, bytes.Length))!=0) 
        {   
          // Translate data bytes to a ASCII string.
          data = System.Text.Encoding.ASCII.GetString(bytes, 0, i);
          Console.WriteLine("Received: {0}", data);
       
          // Process the data sent by the client.
          data = data.ToUpper();

          byte[] msg = System.Text.Encoding.ASCII.GetBytes(data);

          // Send back a response.
          stream.Write(msg, 0, msg.Length);
          Console.WriteLine("Sent: {0}", data);            
        }
         
        // Shutdown and end connection
        client.Close();
      }
    }
    catch(SocketException e)
    {
      Console.WriteLine("SocketException: {0}", e);
    }
    finally
    {
       // Stop listening for new clients.
       server.Stop();
    }

      
    Console.WriteLine("\nHit enter to continue...");
    Console.Read();
  }   
}

#using <System.dll>

using namespace System;
using namespace System::IO;
using namespace System::Net;
using namespace System::Net::Sockets;
using namespace System::Text;
using namespace System::Threading;
void main()
{
   try
   {
      
      // Set the TcpListener on port 13000.
      Int32 port = 13000;
      IPAddress^ localAddr = IPAddress::Parse( "127.0.0.1" );
      
      // TcpListener* server = new TcpListener(port);
      TcpListener^ server = gcnew TcpListener( localAddr,port );
      
      // Start listening for client requests.
      server->Start();
      
      // Buffer for reading data
      array<Byte>^bytes = gcnew array<Byte>(256);
      String^ data = nullptr;
      
      // Enter the listening loop.
      while ( true )
      {
         Console::Write( "Waiting for a connection... " );
         
         // Perform a blocking call to accept requests.
         // You could also user server.AcceptSocket() here.
         TcpClient^ client = server->AcceptTcpClient();
         Console::WriteLine( "Connected!" );
         data = nullptr;
         
         // Get a stream Object* for reading and writing
         NetworkStream^ stream = client->GetStream();
         Int32 i;
         
         // Loop to receive all the data sent by the client.
         while ( i = stream->Read( bytes, 0, bytes->Length ) )
         {
            
            // Translate data bytes to a ASCII String*.
            data = Text::Encoding::ASCII->GetString( bytes, 0, i );
            Console::WriteLine( "Received: {0}", data );
            
            // Process the data sent by the client.
            data = data->ToUpper();
            array<Byte>^msg = Text::Encoding::ASCII->GetBytes( data );
            
            // Send back a response.
            stream->Write( msg, 0, msg->Length );
            Console::WriteLine( "Sent: {0}", data );
         }
         
         // Shutdown and end connection
         client->Close();
      }
   }
   catch ( SocketException^ e ) 
   {
      Console::WriteLine( "SocketException: {0}", e );
   }

   Console::WriteLine( "\nHit enter to continue..." );
   Console::Read();
}