代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication2
{
class Program
{
static void Main(string[] args)
{

        /**
         * 请用户输年份,再输入月份,输出该月的天数.
         * 
         * */
        //请用户输入
        Console.WriteLine("请输入年份");
        //接收用户输入，并转换成数字型字符
        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();
    }
}

}

效果

IMG_20181107_151809.jpg