声明一个教师类和学生类。用多重继承的方式声明一个研究生派生类。-Declare a teacher class and student class. Use multiple inheritance way declare a graduate student derived class.

声明一个教师类和学生类。用多重继承的方式声明一个研究生派生类。在此基础上，在老师类和学生类之上增加一个基类Person。-Declare a teacher class and student class. Use multiple inheritance way declare a graduate student derived class. On this basis, the teacher in class and student class added a base class.

图形类，使用了多重继承和虚函数。可以让学生很好的学习c++类的操作-Graphics classes,using multiple inheritance and virtual functions