Re: derived class and virtual function

#include<iostream>
class Foo
{
public:
virtual Foo* createCopy(){ return new Foo(*this); }
virtual void quack() { std::cout<<"I'm a foo"<<std::endl; }
virtual ~Foo(){}
};

class Bar : public Foo
{
public:
// notice that this createCopy returns a Bar* instead of Foo*
// which is a "pointer to a class that is PUBLICLY derived"
virtual Bar* createCopy(){ return new Bar(*this); }
virtual void quack() { std::cout<<"I'm a bar"<<std::endl; }
};

int main() {
Bar bar;
Foo& br = bar;
Foo* bp = br.createCopy();
bp->quack();
delete bp;
}