1、查询某年某月某日是星期几，2、打印某年某月全月日历，3、打印某年全年日历。-1, the query of a certain period of a day of the week, 2, print a certain period of full-month calendar, 3, print a calendar year.

输入任意年月（公元以后），就可以打印出该月的月历，以及星期几-perpetual calendar