状态模式 02

电话状态机

    enum State
    {
        脱机,
        连接中,
        已连接,
        通话保持 
    }
    
    enum Trigger
    {
       拨打电话,
       挂断电话,
       接收来电,
       通话保持,
       取消等待,
       语音留言 
    }
    class Program
    {

        public static Dictionary<State, List<(Trigger, State)>> rules = new Dictionary<State, List<(Trigger, State)>>
        {
            [State.脱机] = new List<(Trigger, State)>
            {
              (Trigger.拨打电话,State.连接中)
            },
            [State.已连接] = new List<(Trigger, State)>
            {
              (Trigger.挂断电话,State.脱机),
              (Trigger.接收来电,State.已连接)
            },
            [State.连接中] = new List<(Trigger, State)>
            {
              (Trigger.语音留言,State.脱机),
              (Trigger.挂断电话,State.脱机),
              (Trigger.通话保持,State.通话保持),
            },
            [State.通话保持] = new List<(Trigger, State)>
            {
              (Trigger.取消等待,State.连接中),
              (Trigger.挂断电话,State.脱机)
            },

        };

        static void Main(string[] args)
        {
            var state = State.脱机;
            while (true)
            {
                Console.WriteLine($"手机当前状态是{state}");
                Console.WriteLine("选择一个触发：");
                for (int i = 0; i < rules[state].Count; i++)
                {
                    var (t, _) = rules[state][i];
                    Console.WriteLine($"{i}.{t}");
                }
                int input = int.Parse(Console.ReadLine());
                var (_,s)= rules[state][input];
                state = s;
            }
        }
    }