编写日历的程序，输入年度月份后，按日历的形式输出本月。可实现主要功能分析如下：

1.由用户输入年度月份，判断数据是否合法，1900≤year≤2100，1≤month≤12，年份字符串转换成二进制数保存到变量year，month中，否则提示错误

2.判断闰年闰月，修改monthday：闰年将2月天数改为29，否则为28。计算每月有几天，当月的1号是星期几。

3.显示输出月历，用户继续查询的话返回重新继续输入年度月份，否则退出，结束程序。

-Procedures for the preparation of the calendar, enter the month of the year after the calendar month in the form of output. Main functions can be realized as follows: 1. May the year entered by the user to determine the legality of the data, 1900 ≤ year ≤ 2100,1 ≤ month ≤ 12, the year the string into a binary number stored in the variable year, month, otherwise an error 2. to determine leap year leap, modify monthday: leap year to February the number of days to 29, otherwise 28. Calculate a few days each month, 1 month of the week. 3. Display output calendar, users continue to query, then returns to re-enter the month of the year, otherwise the exit end of the program.