There are 3 folders ex1, ex2 and ex3
In each folder there is a readme.txt file.
Read this file before looking at the program file.
Also you can run the executable file.

In folder ex1, program (oop  example)
  create a student file class.dat with field (id,name,sex,class_name)

In folder ex2, program (oop  example)
  Read student from class.dat (id,name,sex,class_name)
  Enter a new class and update the class_name
  save in the file uclass.dat

In folder ex3, program (inheritance example)
  A header file student.h contains the Student class
  which can be used in creatiing a library file library.dat
  The library member record contains
    (id,name,sex,class,name,position,dt_join)
  Hence using inheritance property,
  let lib_member class(id,name,sex,class_name,position,dt_join)
  inherit from student class (id,name,sex,class_name)
  The program reads record (id,name,sex,class_name) from uclass.dat
  and then enters position,dt_join
  and save in the library file library.dat

