// Fig. 7.8: Cylinder.java
// Definition of class Cylinder
public class Cylinder extends Circle {
   protected double height;  // height of Cylinder

   // Cylinder constructor calls Circle constructor
   public Cylinder( double h, double r, double a, double b )
   {
      super( r, a, b );
      setHeight( h );
   }

   // Set height of Cylinder
   public void setHeight( double h )
      { height = ( h >= 0 ? h : 0 ); }

   // Get height of Cylinder
   public double getHeight() { return height; }

   // Calculate area of Cylinder (i.e., surface area)
   public double area()
   {
      return 2 * super.area() +
             2 * 3.14159 * radius * height;
   }

   // Calculate volume of Cylinder
   public double volume() { return super.area() * height; }

   // Convert the Cylinder to a String
   public String toString()
   {
      return super.toString() + "; Height = " + height;
   }
}