Abstract Class Example 1 – C++ Language

#include <iostream>
using namespace std;
class a
{
public:
virtual void display()=0; // Pure Virtual Function
};
class b : public a
{
private:
int roll;
public:
void display()
{
cout<<“enter roll”<<endl;
cin>>roll;
}
};
int main()
{
a *p;
b obj;
p=&obj;
p->display();
obj.display();
return 0;
}