Re: factoring book question and cast question.

Well, the idea is that since both kid1 and kid2 both inherit from base,
then they both should have a common interface, thus eliminating the need
to know the specific type:

#include <iostream>
#include <vector>

class Base {
public:
    virtual void do_something() = 0;
    virtual ~Base();

};

Base::~Base() { }

class Kid1 : public Base {
public:
    virtual void do_something() { std::cout << "I am a Kid1\n"; }

};

class Kid2 : public Base {
public:
    virtual void do_something() { std::cout << "I am a Kid2\n"; }

};

int main()
{
    using std::vector;

    typedef vector<Base*> Container;

    Container container;
    container.push_back(new Kid1);
    container.push_back(new Kid2);

    typedef Container::const_iterator ConstIter;
    for (ConstIter it = container.begin(); it != container.end(); ++it) {
        (*it)->do_something(); // no cast needed here!
    }

    typedef Container::iterator Iter;
    for (Iter it = container.begin(); it != container.end(); ++it) {
        delete *it;
    }

    return 0;

}

Output:
I am a Kid1
I am a Kid2

--
Marcus Kwok