已知道1900-1-1为星期一。
模块分区
//获取用户的正确输入并分别保存到变量year和month中
//声明一个用于保存空白和当月日期数的集合dates
//遍历输出集合dates
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication3
{
class Program
{
static void Main(string[] args)
{
while (true)
{
#region 获取用户输入的年月，保存到变量year，month，死循环
int year, month;
while (true)
{
Console.Write("请输入年份（1900到2100）:");
year = int.Parse(Console.ReadLine());
if (year < 1900 || year > 2100)
{
Console.Write("输入年份错误，请按回车键继续");
Console.ReadLine();
Console.Clear();
}
else//输入年份正确
{
Console.Write("请输入月份(1到12):");
month = int.Parse(Console.ReadLine());
if (month < 1 || month > 12)
{
Console.WriteLine("输入月份错误，请按回车键继续");
Console.ReadLine();
Console.Clear();
}
else
{
break;
}
}
}
#endregion
#region 集合dates 依次保存空白和每月的天数date
List<string> dates = new List<string> { };
#region 求空白的数量，保存到变量space中，并保存到集合dates中
//已知1900-1-1是星期1，求year-month-1与其的关系
//求space=（year-month-1）的星期几-1。space= dayOfWeek-1
//求dayOfWeek,为与1900-1-1隔多少天后，设为变量crossDays，dayOfWeek=crossDays%7+1
//求crossDays，从1900-1-1到year-month-1经过了多少天，为1900到year-1经过的总天数，加，从year年中的1月1日到month月1日的天数
//先求从1900-1-1，到year-month-1经过的天数
int space, dayOfWeek, crossDays, crossDaysOfYear = 0, crossDaysOfMonth = 0;
for (int i = 1990; i <= year - 1; i++)
{
//循环变量i为某一年
if ((i % 4 == 0 && i % 100 != 0) || (i % 400 == 0))//闰年
{
crossDaysOfYear += 366;
}
else
{
crossDaysOfYear += 365;
}
}
for (int i = 1; i <= month-1; i++)
{
//循环变量i为某月
if (i == 2)
{
if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0))
{
crossDaysOfMonth += 29;
}
else
{
crossDaysOfMonth += 28;
}
}
else if (i == 1 || i == 3 || i == 5 || i == 7 || i == 8 || i == 10 || i == 12)
{
crossDaysOfMonth += 31;
}
else
{
crossDaysOfMonth += 30;
}
}
crossDays = crossDaysOfYear + crossDaysOfMonth;//相隔的总天数
dayOfWeek = crossDays % 7 + 1;
space = dayOfWeek - 1;
for (int i = 0; i < space; i++)//添加空白字符串到集合中去
{
dates.Add("");
}
#endregion
#region 当月的天数date，再添加到集合中去
int days;//用户输入month的当月天数
if (month == 2)
{
if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0))
{
days = 29;
}
else
{
days = 28;
}
}
else if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12)
{
days = 31;
}
else
{
days = 30;
}
for (int i = 1; i <= days; i++)
{
dates.Add(i.ToString());
}
#endregion
#endregion
#region 遍历输出集合dates
Console.WriteLine("===================================");
Console.Write("一\t二\t三\t四\t五\t六\t日\t");
for (int i = 0; i < dates.Count; i++)
{
if (i % 7 == 0)
{
Console.WriteLine();//输出换行的意思
}
Console.Write(dates[i] + "\t");
}
Console.WriteLine();
Console.WriteLine("===================================");
#endregion
Console.Write("按回车键继续");
Console.ReadLine();
Console.Clear();
}
}
}
}
原文地址：https://www.cnblogs.com/yt0817/p/11625973.html