#include <stdio.h>

class A{
        public:
        virtual int func(int a){return a;};
};

class B:public A{
        public:
        int func(int a){return a+2;};
};

int main(){
        A *ab = new A();
        A *bb = (A *)new B();
        printf("%d, %d",ab->func(1),bb->func(1));
}