#include <iostream>
using namespace std;
 
struct A1
{
  void func() { cout << "classA1::func()" << endl; }
};
struct A2
{
  virtual void func() { cout << "classA2::func()" << endl; }
};
struct B1 : public A1
{
  void func() { cout << "classB1::func()" << endl; }
};
struct B2 : public A2
{
  void func() { cout << "classB2::func()" << endl; }
};
int main()
{
  B1 b1;
  B2 b2;
 
  A1* pa1;
  A2* pa2;
 
  pa1 = &b1;
  pa2 = &b2;
 
  pa1->func(); //①
  pa2->func(); //②
  return 0;
}

I2luY2x1ZGUgPGlvc3RyZWFtPgp1c2luZyBuYW1lc3BhY2Ugc3RkOwoKc3RydWN0IEExCnsKICB2b2lkIGZ1bmMoKSB7IGNvdXQgPDwgImNsYXNzQTE6OmZ1bmMoKSIgPDwgZW5kbDsgfQp9OwpzdHJ1Y3QgQTIKewogIHZpcnR1YWwgdm9pZCBmdW5jKCkgeyBjb3V0IDw8ICJjbGFzc0EyOjpmdW5jKCkiIDw8IGVuZGw7IH0KfTsKc3RydWN0IEIxIDogcHVibGljIEExCnsKICB2b2lkIGZ1bmMoKSB7IGNvdXQgPDwgImNsYXNzQjE6OmZ1bmMoKSIgPDwgZW5kbDsgfQp9OwpzdHJ1Y3QgQjIgOiBwdWJsaWMgQTIKewogIHZvaWQgZnVuYygpIHsgY291dCA8PCAiY2xhc3NCMjo6ZnVuYygpIiA8PCBlbmRsOyB9Cn07CmludCBtYWluKCkKewogIEIxIGIxOwogIEIyIGIyOwoKICBBMSogcGExOwogIEEyKiBwYTI7CgogIHBhMSA9ICZiMTsKICBwYTIgPSAmYjI7CgogIHBhMS0+ZnVuYygpOyAvL+KRoAogIHBhMi0+ZnVuYygpOyAvL+KRoQogIHJldHVybiAwOwp9