class Rect; bool intersect( Rect* ); bool intersect( Ellipse* ); bool intersect( Polygon* ); ...

##</code><code>##

#include <iostream>

using namespace std;

class Shape { public: virtual ~Shape(){}; };
class Polygon : public Shape { };
class Circle : public Shape { };

void ShowType(Shape *obj)
{
  cout << "Shape" << endl;
}

void ShowType(Polygon *obj)
{
  cout << "Polygon" << endl;
}

void ShowType(Circle *obj)
{
  cout << "Circle" << endl;
}

int main()
{
  Shape *shape;

  shape = new Polygon();
  ShowType(shape);

  shape = new Circle();
  ShowType(shape);
}

##</code><code>##

Shape
Shape

##</code><code>##

void ShowType(Shape *obj)
{
  if (dynamic_cast<Polygon*>(obj))
    ShowType(dynamic_cast<Polygon*>(obj));
  else if (dynamic_cast<Circle*>(obj))
    ShowType(dynamic_cast<Circle*>(obj));
  else
   cout << "Shape" << endl;
}

##</code><code>##

Polygon
Circle