using System;

using System.Collections.Generic;

using System.IO;

using System.Net;

using System.Net.Sockets;

using System.Text;

using System.Threading;

​

namespace ConsoleApplication1

{

    class Program

    {       

        static void Main(string[] args)

        {

            TcpListener tcpListener = new TcpListener(IPAddress.Any, 4000);

            tcpListener.Start();

            Console.WriteLine("Сервер запущен");

            int clientId = 0;

            List<StreamWriter> writers = new List<StreamWriter>();

            new Thread(() =>

            {

                while (true)

                {

                    string lineToSend = Console.ReadLine();

                    foreach (StreamWriter writer in writers)

                    {

                        writer.WriteLine("Инфо: " + lineToSend);

                    }

                }

            }).Start();

            while (true)

            {

                TcpClient tcpclient = tcpListener.AcceptTcpClient();

                clientId++;

                new Thread(() =>

                {

                    int thisClientId = clientId;

                    NetworkStream nstream = tcpclient.GetStream();

                    Console.WriteLine("Клиент " + thisClientId + " подключен");

                    StreamWriter writer = new StreamWriter(nstream, Encoding.UTF8) { AutoFlush = true };

                    StreamReader reader = new StreamReader(nstream, Encoding.UTF8);

                    writers.Add(writer);

                    new Thread(() =>

                    {

                        while (true)

                        {

                            string inputline = reader.ReadLine();

                            Console.WriteLine("Клиент " + thisClientId + " написал: " + inputline);

                            writer.WriteLine(inputline.Length);

                        }

                    }).Start();

                }).Start();

            }

        }

    }

}

​