Pure Virtual Function in C++

• A class containing the pure virtual function cannot be used to declare the objects of its own, such classes are known as abstract base classes.
• Pure virtual function can be defined as:
• virtual void show() = 0;   

 

#include <iostream>

using namespace std;

class A

{

public:

   

 virtual void show()=0;

 

  

};

class B: public A

{

    public:

   

   void show()

  {

    

      cout<<"India"<<endl;

  }

    

 

};

int main() {

 

    A *a;  

    B b;  

    a = &b;  

   a->show();  

//   A a1;   Error

//A *a2=new A;  Error

    return 0;  

 

 

}