设计一个虚基类——学生类，包含学号、姓名和年龄保护数据成员以及相关的成员函数；由学生类派生出学生干部类，包含职务和学院保护数据成员以及相关的成员函数；再由学生类派生出优秀学生类；然后由学生干部类和优秀学生类派生出优秀学生干部类。

设计一个利用文件处理方式实现对学校学生（包括学生干部、优秀学生和优秀学生干部）进行管理，具有增加数据、更新数据、查询数据、删除数据以及重组文件的功能。（删除数据在记录中做删除标志，重组文件指在物理上删除有删除标志的记录）另外要求分别统计这三类学生的人数以及所有学生的总数。-Design a virtual base class- class students, including student number, name and age to protect data members and member functions related　student class derived　class student leaders, including members of their duties and colleges to protect data and associated member function　then by student class derived class of outstanding students　and then by the student leaders and outstanding student class class class derived outstanding student leaders.

Design a way to achieve the use of document processing school students (including student leaders, outstanding student and outstanding student leaders) to manage, with increased data, update data, query data, delete function data as well as restructuring of the file. (Delete data in the record do delete flag, restructuring document refers to physically remove the deleted record mark) additionally required number of statistics that were three groups of students and the total number of all students.