public static void ShowDemo() { Console.WriteLine("##### 一个聊天室的 中介. #####"); // Create chatroom Chatroom chatroom = new Chatroom(); // Create participants and register them Participant George = new NonAdmin("张三"); Participant Paul = new NonAdmin("李四"); Participant Ringo = new NonAdmin("王五"); Participant John = new NonAdmin("赵六"); Participant Yoko = new Admin("田七"); chatroom.Register(George); chatroom.Register(Paul); chatroom.Register(Ringo); chatroom.Register(John); chatroom.Register(Yoko); // Chatting participants Yoko.Send("赵六", "你好, 赵六!"); Paul.Send("王五", "服务器有点卡。"); Ringo.Send("张三", "测试测试..."); Paul.Send("赵六", "你那里网络卡不卡?"); John.Send("田七", "服务器是不是挂了? 管理员。"); }