static void Main(string[] args)
        {           
            int recv;//用于表示客户端发送的信息长度
            byte[] data = new byte[1024];//用于缓存客户端所发送的信息,通过socket传递的信息必须为字节数组
            IPEndPoint ipep = new IPEndPoint(IPAddress.Any, 9050);//本机预使用的IP和端口
            Socket newsock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            newsock.Bind(ipep);//绑定
            newsock.Listen(10);//监听
            Console.WriteLine("waiting for a client");
            Socket client = newsock.Accept();//当有可用的客户端连接尝试时执行，并返回一个新的socket,用于与客户端之间的通信
            IPEndPoint clientip = (IPEndPoint)client.RemoteEndPoint;
            Console.WriteLine("connect with client:" + clientip.Address + " at port:" + clientip.Port);
            string welcome = "welcome here!";
            data = Encoding.ASCII.GetBytes(welcome);
            client.Send(data, data.Length, SocketFlags.None);//发送信息
            try
            {
                while (true)
                {//用死循环来不断的从客户端获取信息
                    data = new byte[1024];
                    recv = client.Receive(data);
                    Console.WriteLine("recv=" + recv);
                    if (recv == 0)//当信息长度为0，说明客户端连接断开
                        break;
                    Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv));
                    client.Send(data, recv, SocketFlags.None);//发送信息
                }
            }
            catch
            {
                Console.WriteLine("Disconnected from" + clientip.Address);
            }
            client.Close();
            newsock.Close();           
        }

        static void Main(string[] args)
        {
            byte[] data = new byte[1024];
            Socket newclient = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            Console.Write("please input the server ip:");
            string ipadd = Console.ReadLine();
            Console.WriteLine();
            Console.Write("please input the server port:");
            int port = Convert.ToInt32(Console.ReadLine());
            IPEndPoint ie = new IPEndPoint(IPAddress.Parse(ipadd), port);//服务器的IP和端口
            try
            {
                //因为客户端只是用来向特定的服务器发送信息，所以不需要绑定本机的IP和端口。不需要监听。
                newclient.Connect(ie);
            }
            catch (SocketException e)
            {
                Console.WriteLine("unable to connect to server");
                Console.WriteLine(e.ToString());
                return;
            }

            newclient.Send(Encoding.Default.GetBytes("watchdog"));
            int recv = newclient.Receive(data);
            string stringdata = Encoding.ASCII.GetString(data, 0, recv);
            Console.WriteLine(stringdata);
            while (true)
            {
                string input = Console.ReadLine();
                if (input == "exit")
                    break;
                newclient.Send(Encoding.ASCII.GetBytes(input));
                data = new byte[1024];
                recv = newclient.Receive(data);
                stringdata = Encoding.ASCII.GetString(data, 0, recv);
                Console.WriteLine(stringdata);
            }
            Console.WriteLine("disconnect from sercer");
            newclient.Shutdown(SocketShutdown.Both);
            newclient.Close();
        }