输入年月日，计算为该年的第几天！能识别不合理日期的输入，并能及时停止程序-Enter year, month date, calculated for the first few days in! Can identify the input date is unreasonable, and can stop the program in time

输入日期计算该日是星期几的小程序 希望对大家学习有帮助 共同进步-Enter the date the day of the week a small program you want to learn to help make progress together

日期时间工具函数,含有计算星期几,从0000年以来天数和毫秒数,日期加减和日期比较等()