public class Demo
{
    public static void main(String[] args) {
        Cylinder bottom = new CylinderImpl(10.2, 3.3);
        Cylinder middle = new CylinderImpl(8.3, 3.1);
        Cylinder top    = new CylinderImpl(3.4, 2.5);
        
        System.out.println("Volume of bottom floor:   " + bottom.getVolume());
        System.out.println("Volume of middle floor:   " + middle.getVolume());
        System.out.println("Volume of top floor:      " + top.getVolume());
        System.out.println("Volume of the whole cake: " + 
           new BirthdayCake(bottom, middle, top).getCakeVolume());
        System.out.println("Volume of default cake:   " +
           new BirthdayCake().getCakeVolume());
    }
}