09_12_2008.cpp

#include<iostream>
using namespace std;

class D;
class B{
    public: virtual D* f() =0;
};

class C{
    public:
        virtual C* g();
        virtual B* h() =0;
};

class D: public B, public C{
    public:
        D* f() {cout << "D::f"; return new D;}
        D* h() {cout << "D::h"; return dynamic_cast<D*>(g());}
};

C* C::g() {
    cout << "C::g";
    B* p = dynamic_cast<B*>(this);
    if(p) return p->f(); 
        else return this;
}

class E: public D{
    public:
        E* f() {
            cout << "E::f";
            E* p = dynamic_cast<E*>(g());
            if(p) return p;
                else return this;
        }
};

class F: public E{
    public:
        E* g() {
            cout << "F::g"; return new F;
        }
        E* h(){
            cout <<"F::h";
            E* p = dynamic_cast<E*>(E::g());
            if(p) return p;
                else return new F;
        }
};

B* p; C* q; D* r;

int main(){
    //p = new E; p->h(); 
    //p = new E; p->f();ER
    p = new D; (dynamic_cast<D*>(p))->h(); cout << endl;
    q = new D; q->g();  cout << endl;
    //q = new E; q->h();ER
    //q = new E; q->g();ER
    //r = new E; r->f();ER
    r = new F; r->f(); cout << endl;
    r = new F; r->g(); cout << endl;
    r = new F; r->h();
}