upcast

#include
using namespace std;

class A{
protected:
virtual void print() { cout << "A" << endl; }
void print2() { cout << "AA" << endl; } // how about adding virtual?
};

class B {
public:
virtual void print() { cout << "B" << endl; }
void print2() { cout << "BB" << endl; }
};

class C : public A, public B{
public:
void print2() { cout << "CC" << endl; }
};

int main() {
C c;
B* p = &c;
p->print2();
}

Answer: BB
if using 'virtual', then answer is CC

When assigned the address of the object to base class, the new defined function in derived class will be un-accessible to that pointer. If a function is defined 'virtual' in base class and is overrided it in derived class, the copy in derived class will be called. Otherwise, the copy in base class is called.