Re: Confusion about inheritance and the allocating memory via new

I am compiling the following code, main.cpp, as follows:
gcc main.cpp

I get the following compile error:
main.cpp: In function `int main()':
main.cpp:28: no matching function for call to `CPolygon::area()'

The code is listed below:

#include <iostream>
using namespace std;

class CPolygon {
  public:
    virtual void set_values (int a, int b) { width=a; height=b; };

  protected:
    int width, height;
  };

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

int main ()
{
 CPolygon * ppoly1 = new CRectangle;
 ppoly1->set_values (4,5);
 cout << ppoly1->area() << endl;
 return 0;

}

Why does this not compile?