static void Main(string[] args) { var chatRoom = new ChatRoom(); var user1 = new CommonUser("小明"); var user2 = new GoldenUser("小豪"); var user3 = new Administrator("小蛤"); chatRoom.register(user1); chatRoom.register(user2); chatRoom.register(user3); user1.send("Hello,world"); user2.send("买辆兰博基尼怎么样"); user3.send("开门,快递"); Console.ReadKey(); }