(1)日历显示功能。能根据系统日期进行初始化，如果没有任何输入，则显示系统日期所在月份的月历。
（2）日历查询、闰年判断功能。输入日期进行查询，显示查询日期所在月份的月历，还将显示所在年份是否为闰年
（3）参数检查功能。如果输入日期不合法，查询将被拒绝，并显示提示信息。
（4）调整年份、月份和日期，并显示调整后的日期及月历。((1) calendar display function. It can be initialized according to the system date. If there is no input, the calendar of the month of the system's date is displayed.
(2) calendar query, leap year judgment function. Enter the date to query, display the date of the month in which the query date is located, and also show whether the year is a leap year
(3) parameter check function. If the input date is illegal, the query will be rejected and the prompt information will be displayed.
(4) adjust the year, month and date, and display the adjusted date and calendar.)