可以进行1970~2050年日期的运算，有，判断日期是否有效，是星期几，判断两日期相差几天，判断某日期前后n天是什么日期的功能。-Operation can be carried out　1970 to 2050 the date has to determine whether the effective date, day of the week, the date of judgment two days apart, before and after judgment day is a date n What s the date.