TCPEchoClient

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

class TcpEchoClient
{
    static void Main(string[] args)
    {
        if ((args.Length < 2 || args.Length > 3))
            throw new ArgumentException("Parameters: <server> <word> (<port>)");

        string server = args[0]; // read the server's name from the first argument of the console's input stream

        byte[] byteBuffer = Encoding.ASCII.GetBytes(args[1]); // get the echo data from console's input stream

        int serverPort = (args.Length == 3) ? Int32.Parse(args[2]) : 7;

        TcpClient client = null; // variable to hold the socket
        NetworkStream netStream = null; // allows data to be sent

        try
        {
            client = new TcpClient(server, serverPort);

            Console.WriteLine("Connected to server.. sending echo string");

            netStream = client.GetStream();
            netStream.Write(byteBuffer, 0, byteBuffer.Length); // send string to echo server

            Console.WriteLine("Sent {0} bytes to server...", byteBuffer.Length);

            int totalBytesRcvd = 0;
            int bytesRcvd = 0;

            while (totalBytesRcvd < byteBuffer.Length)
            {
                // repeatedly recieve bytes until it's same number as amount sent
                if ((bytesRcvd = netStream.Read(byteBuffer, totalBytesRcvd, byteBuffer.Length - totalBytesRcvd)) == 0)
                { // remember read does nothing until some data is available
                    Console.WriteLine("Connection closed prematurely.");
                    break;
                }
                totalBytesRcvd += bytesRcvd;
            }
        }catch(Exception e)
        {
            Console.WriteLine(e.Message);
        }
        finally
        {
            netStream.Close();
            client.Close();
        }
    }
}