12 void move(double dx
, double dy
);
13 virtual double area(void) = 0;
14 virtual double perimeter(void) = 0;
18 class Circle
: public Shape
{
22 Circle(double r
) : radius(r
) { };
23 virtual double area(void);
24 virtual double perimeter(void);
27 class Square
: public Shape
{
31 Square(double w
) : width(w
) { };
32 virtual double area(void);
33 virtual double perimeter(void);