Re: derived class and virtual function

On 8/13/2010 10:29 AM, subramanian100in@yahoo.com, India wrote:


It allows you for example to write code like this (polymorphic copy)

#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;
}