请用户输年份,再输入月份,输出该月的天数.

 ```             
              Console.WriteLine("请输入一个年份");
               int year = Convert.ToInt32(Console.ReadLine());
               Console.WriteLine("请输入一个月份");
                int month = Convert.ToInt32(Console.ReadLine());
                if (month >= 1 && month <= 12)
                {
                    int day = 0;//存储天数
                    switch (month)
                    {
                        case 1:
                        case 3:
                        case 5:
                        case 7:
                        case 8:
                        case 10:
                        case 12: day = 31;
                            break;
                        case 2:
                            if ((year % 400 == 0) || (year % 4 == 0 && year % 100 != 0))
                            {
                                day = 29;
                            }
                            else
                            {
                                day = 28;
                            }
                            break;
                        default: day = 30;
                            break;
                    }//swich
                    Console.WriteLine("{0}年{1}月有{2}天", year, month, day);
                }//if
                else
                {
                    Console.WriteLine("月份必须在1~12月之间，程序退出！！！");
                }
                    Console.Readkey();

![2.png](https://img.haomeiwen.com/i14498195/e741e2385f93c7d2.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)