Написать класс на C++ 'Банковский счет'.

Помогите студенту! Вот задание как его сформулировал учитель :

Your program should have a base class, and at least 1 derived class in header files. The main program should update the data and write to and read frоm random access files for the base class and derived class data. Using pointers, static members, and other (such as virtual) where appropriate ,can earn some extra points. The minimum that your base class should have is 5 data members. These should be character arrays (string) for names, and double (for salary or balance) , and integers (id number, date, etc). Your project should be either a persoinnel databse (employees, and managers, ) or bank accounts, or sales staff and custumers.

Не надо ничего сложного, я не учусь на программиста, это знакомство с C++.