理解和掌握运算符重载，了解静态变量和const成员函数。

实验内容：

（1）设计一个名为Date的日期类，完成基本的日期处理功能。

　　（2）扩充实例编程中的日期类，为Date类增加一个成员函数，可以判断一个日期是否是系统的当前日期。从键盘输入你的生日，如果今天是你的生日则显示“HappyBirthday！”，否则显示“还有XX天是你的生日”或“你的生日已经过去了XX天，明年的生日要再等YY天”。

　　（3）仿照Date类设计一个Time类，设计多个重载的构造函数，可以设置时间、进行时间的加减运算、按各种可能的格式输出时间。-Understand and master operator overloading, understanding static const member variables and functions. Experiment: (a) Design a class named Date date, the completion date of the basic processing functions. (2) extend the date in the class examples of programming for the Date class adds a member function, you can determine whether a date is the system' s current date. From the keyboard to enter your birthday, if today is your birthday is displayed " HappyBirthday!" , Otherwise " there is your birthday XX days"　or " your birthday has passed after XX days next year' s birthday have to wait YY days. "　(3) Design a class modeled Date Time class, designing several overloaded constructors, you can set the time for time of addition and subtraction, according to a variety of possible formats output time.