implicit casting?

[vitalishe]

I am just making sure I understand the difference between the two codes correctly.
I am creating two instances of class CRectangle but working with them as if they were instances of CPolygon.

#include <iostream>

using namespace std;

class CPolygon{
   protected:
      double width, height;
   public:
      void set_values (int a, int b){ width=a; height=b;};
      virtual double area(){return 0;};
};

class CRectangle: public CPolygon{
  public:
    double area (){ return (width * height); }
};


int main () {
   CPolygon * pRect = new CRectangle;
   CPolygon rect = *(new CRectangle);

   pRect->set_values(4,5);
   rect.set_values(4,5);

   cout << pRect->area() << endl;
   cout << rect.area() << endl;

   return 0;
}

- In the case of 'pRect' the output is 20, because in the CPolygon the function area() is declared as virtual.

- On the other hand, for 'rect' the output is 0. Is this because there is an implicit casting going on? That is 'rect' is really an instance of CPolygon?

[vlad from moscow]

rect is an object of type CPolygon as it was defined by your. *(new Crectangle) was implicitly converted to Cpolygon.