定义一个Student类，其中包括学号、姓名、性别、出生年月等属性以及init( )——初始化各属性、display( )——显示各属性、modify( )¬ ——修改姓名等方法。实现并测试这个类。

从上题的Student类中派生出Graduate(研究生)类，添加属性：专业subject、导师adviser。重载相应的成员方法

-Define a Student class, including the Student ID, name, gender, date of birth and other attributes as well as the init ()- initialize the attributes, display ()- showing all the properties, modify () ¬ - modify the name and other methods . Achieve and test the class. From the title of the Student class derived Graduate (graduate) class, add the attributes: the professional subject, teacher adviser. Overloaded the corresponding member methods