定义一个钟表类，包括三个私有成员，分别为小时、分钟、秒，在此基础上，请重载自增运算符（++）和自减运算符（--）为类的成员函数，使得钟表类的对象能进行基于秒数的时间变化。-Defines a clock class, including three private members, hours, minutes, seconds, respectively, on this basis, overload the auto increment operator (++) and decrement operator (--) as a member function of a class, watch and class objects can change based on the number of seconds of time