Can anyone explain why the last line works? It seems like it is trying to cast a CRectangle as a CTriangle (which I imagine should fail?) but it outputs "5" as the function should.
// virtual members
#include <iostream>
using namespace std;
class CPolygon {
protected:
int width, height;
public:
void set_values (int a, int b)
{ width=a; height=b; }
virtual int area () = 0;
//{ return (0); }
};
class CRectangle: public CPolygon {
public:
int area ()
{ return (width * height); }
};
class CTriangle: public CPolygon {
public:
int area ()
{ return (width * height / 2); }
int triFunc(){return 5;}
};
int main ()
{
CPolygon* ppoly1 = new CRectangle;
CPolygon* ppoly2 = new CTriangle;
ppoly1->set_values (4,5);
ppoly2->set_values (4,5);
cout << ppoly1->area() << endl;
cout << ppoly2->area() << endl;
std::cout << dynamic_cast<CTriangle*>(ppoly2)->triFunc() << std::endl; //works (and should work)
std::cout << dynamic_cast<CTriangle*>(ppoly1)->triFunc() << std::endl; //works (but seems like it shouldn't)
return 0;
}Thanks,
David
