Example of use of "inheritance"

This directory contains
a) readme.txt
b) student.h   -header file that contains the class Student
c) eca_lib.cpp -program that reads in  student from uclass.dat
                and add details only of students who are library members.
d) eca_lib.exe -run time program
e) uclass.dat  -input file of student record (id,name,sex,class_name)

In the previous example ex2, the Student class has attributes (fields)
Student { id,name,sex,class_name}
and has member functions  
//     readrec(istream &is) -to read a record id,name,class_name
//     show() -display id,name,class_name
//     save(ostream &os)  -to save a record

This class Student and its member functions can be used in another
class  for library members Lib_member.
Lib_member{id,name,sex,class_name,position,dt_join)

              Student{id,name,sex,class_nme}
                           |
               Lib_member{position, dt_join}

By allowing Lib_member to inherit all the attributes and member functions
of Student, Lib_member will be able to use the functions
    readrec,show, save (which  was defined in Student)

The program eca_lib.cpp
      reads in a record (id,name,sex,class_name) from uclass.dat
      Display the record
      Ask if this is a member?
      if 'Y' then enter the position and date join
                  save the record in file library.dat
      Repeat for all records in uclass.dat


