static void Main(string[] args)

        {

            while (true)

            {

                int a;

                Random r = new Random();

                a = r.Next(0,24);

                  Console.WriteLine(a);

                if (a >= 0 && a < 6)

                {

                    Console.WriteLine("凌晨"+a+"点");

                }

                else if (a >= 6 && a < 12)

                {

                    Console.WriteLine("上午" + a + "点");

                }

                else if (a >= 12 && a < 18)

 

                {

                    Console.WriteLine("下午" + (a-12) + "点");

                }

 

                else if (a >= 18 && a <= 24)

                {

                    Console.WriteLine("晚上" + (a - 12) + "点");

                }

                else

                {

                    Console.WriteLine("对不起，出错了");

                } 

            }