class Lens extends InventoryItem
{
   public Lens() 
   {
       super("The Lens class");
       isZoom = true;
       focalLength = 2.0;
   } // constructor

   // methods speific to Lens
   void print()
   {
       System.out.println( getDescription() + " : " + getQuantityOnHand());
       System.out.println( " focal length : " + focalLength);
   } // print

   private boolean isZoom;
   private double focalLength;   
} // class Lens