C ++ program : Type Casting example

#include <iostream>
using namespace std;
class A {
protected:
    int i;
public:
    A(int a = 0) : i(a) {}
void fun() { cout << i; }
};
class B :public A{
public:
    B(int a = 0) : A(a) {}
 virtual void fun() { cout << i*10; }
};
class C :public B{
public:
    C(int a = 0) : B(a) {}
 virtual void fun() { cout << i*15; }
};
int main(){
    int num;
    cin >> num;
    B *bp = new C(num);
    bp->fun();
    return 0;
}

Thanks
Happy Programming !