Pure Virtual Function

//A program to illustrate how to declare a pure virtual function and equate it to zero as it

//   does not have any function parts.//

#include <iostream.h>

#include <conio.h>

class base {

   private :

      int x;

      float y;

   public :

      virtual inline void getdata() = 0;

      virtual inline void display() = 0;

};

class derivedB : public base {

   private :

      long int rollno;

      char name[20];

   public :

      void getdata();

      void display();

};

void derivedB :: getdata()

{

   cout << " enter roll no of student \n";

   cin >> rollno;

   cout << " enter name of a student \n";

   cin >> name;

}

void derivedB :: display()

{

   cout << " roll number, stdent's name \n";

   cout <<  rollno << '\t' << name << endl;

}

void main()

{

  clrscr();

   base *ptr;

   derivedB obj;

   ptr=&obj;

   ptr->getdata();

   ptr->display();

   getch();

}