#include <iostream.h>

class Circle;
class Polygon;

class Shape { 
    public: 
    virtual ~Shape(){}; 
    virtual void ShowType() {
        cout << "Shape" << endl;
    }
    virtual void intersect( Shape *that ) {
        cout << "Shape:intersect" << endl;
    }
    virtual void intersect_( Circle * );
    virtual void intersect_( Polygon * );
};

class Polygon : public Shape { 
    public:
    virtual void ShowType() {
        cout << "Polygon" << endl;
    }

    virtual void intersect_( Polygon *that ) { that->intersect( this ); }
    virtual void intersect( Polygon *that ) {
        cout << "Intersect Polygon with Polygon" << endl;    
    }

    void Polygon::intersect_( Circle *that );
    
    virtual void intersect( Shape *that ) { that->intersect_( this ); }
    virtual void intersect( Circle *that ) {
        cout << "Intersect Polygon with Circle" << endl;  
    }
};
void Shape::intersect_( Polygon * ) { }

class Circle : public Shape { 
    public:
    virtual void ShowType() {
        cout << "Circle" << endl;
    }
    virtual void intersect_( Circle *that ) { that->intersect( this ); }
    virtual void intersect( Circle *that ) {
        cout << "Intersect Circle with Circle" << endl;    
    }

    virtual void intersect_( Polygon *that ) { that->intersect( this ); }
    virtual void intersect( Polygon *that ) {
        cout << "Intersect Circle with Polygon" << endl;    
    }
    virtual void intersect( Shape *that ) { that->intersect_( this ); }
};

void Shape::intersect_( Circle * ) { }

void Polygon::intersect_( Circle *that ) { that->intersect( this ); }


int main() {
    Shape *circle = new Circle;
    circle->ShowType();
    
    Shape *polygon  = new Polygon;
    polygon->ShowType();
    
    circle->intersect( polygon ); 
    circle->intersect( circle ); 
    polygon->intersect( circle );
    polygon->intersect( polygon );
    
    return 1;
}