Tente assim: class Color{
private:
int r,g,b;
public:
Color(){
this->r = 0;
this->g = 0;
this->b = 0;
}
Color(int r, int g, int b){
this->r = r;
this->g = g;
this->b = b;
}
...
};
class CWindow {
private:
int x, y;
public:
CWindow(Color cor, int x=0, int y=0){
...
}
};