编写程序实现目标机和宿主机的通信。该程序分为客户端（Clien.c ）和服务器端（Server.c ），用宿主机做服务器，目标机做客户机，服务端开一个端口(2000),等待客户的连接请求。一旦有客户连接,服务器端打印出客户端的IP地址和端口,并且向客户端发送欢迎信息和时间。(Write the program to realize the communication between the target machine and the host. The program is divided into the client (Clien.c) and the server side (Server.c). The host is used to make the server, the target machine is the client, and the server opens a port (2000), waiting for the customer's connection request. Once a client is connected, the server prints out the IP address and port of the client and sends the welcome information and time to the client.)