How can I implement polymorphism in this program?

[maxg316]

Hi, i've got a prgram for a college system which allows a user to determine the overall grades for a student. What I want to do is add polymorphism to this program, but im sure how I could? the program uses a base class and a derived class.

Heres the code for main:

#include "HNDStudent.h"
#include "NatdipStudent.h"


int main(int argc, char *argv[])
{
    string sname, sQT,g;
    double sID;
    char si;
    int sQL,sY;
        
    HNDstudent s2009("x", 'x', 000, 0, "x", 0, "incomplete");
    
    s2009.Set_surname(sname);
    s2009.Set_initial(si);
    s2009.Set_ID(sID);
    s2009.Set_level(sQL);
    s2009.Set_qual_title(sQT);
    s2009.Set_year(sY);
    s2009.Set_grade(g);
    
   
   cout<<s2009.Get_surname()<<endl; //inherited functions 
   cout<<s2009.Get_initial()<<endl;;
   cout<<s2009.Get_ID()<<endl;;
   cout<<s2009.Get_level()<<endl;;
   cout<<s2009.Get_qual_title()<<endl;;
   cout<<s2009.Get_year()<<endl;
   cout<<s2009.Get_grade()<<endl;
       
   
    
    system("PAUSE");
    return EXIT_SUCCESS;
}