/** Functions to calculate the area of pizza purchased, given a diameter.
 *
 * @author Ian Barland
 * @version 2007.Jan.10
 */
class PizzaServer {

  /** Calculate the area of a pizza, given its diameter.
   * @param diam The diameter of the pizza, in inches.
   * @return The area of the pizza, in square inches.
   *    p.pizzaArea( 0) =    0
   *    p.pizzaArea( 2) =~   3.14
   *    p.pizzaArea(12) =~ 113.04
   *    p.pizzaArea(16) =~ 209.96
   *    p.pizzaArea(20) =~ 314
   */
  double pizzaArea( double diam ) {
    double radius;
    radius = diam/2;
    return 3.14 * radius * radius;
    }


  /** Calculate the are of *topping* on a pizza, given its diameter.
   *  Krusteaze pizza has 3" of crust all the way around.
   * @param diam The diameter of the pizza (in inches); must be 6 or more.
   * @return The amount of topping (in square inches)
   *  p.toppingArea( 6) = p.pizzaArea(  6 - 2*3 )  =    0
   *  p.toppingArea( 8) = p.pizzaArea(  8 - 2*3 )  =~   3.14
   *  p.toppingArea(12) = p.pizzaArea( 12 - 2*3 )  =~  28.26
   */
  double toppingArea( double diam ) {
    double innerDiam;
    innerDiam = diam - 2*3;
    /* We subtract the part of the diameter which is crust: 3" on each side. */
    return this.pizzaArea( innerDiam );
    }


  /** Calculate the are of *crust* on a pizza, given its diameter.
   *  Krusteaze pizza has 3" of crust all the way around.
   * @param diam The diameter of the pizza (in inches); must be 6 or more.
   * @return The amount of crust (in square inches)
   *  p.crustArea( 6) = p.pizzaArea( 6) - p.toppingArea( 6) =~  28.26
   *  p.crustArea(12) = p.pizzaArea(12) - p.toppingArea(12) =~  84.78
   *  p.crustArea(20) = p.pizzaArea(20) - p.toppingArea(20) =~ 160.14
   */
  double crustArea( double diam ) {
    double totalArea;
    totalArea = this.pizzaArea(diam);

    double innerArea;
    innerArea = this.toppingArea(diam);

    return (totalArea - innerArea);
    }



  /** Calculate the area of pizza ordered, given its diameter,
   * based on the "free foot friday" promo of itec120-lect01c.
   * @param diam The diameter of the pizza ordered, in inches.
   * @return The total area of pizza received, in square inches.
   *  p.friPizzaArea( 0) = p.pizzaArea( 0) + pizzaArea(12) =~ 113.04
   *  p.friPizzaArea( 2) = p.pizzaArea( 2) + pizzaArea(12) =~ 116.18
   *  p.friPizzaArea(12) = p.pizzaArea(12) + pizzaArea(12) =~ 226.08
   *  p.friPizzaArea(20) = p.pizzaArea(20) + pizzaArea(12) =~ 427.04
   */
  double friPizzaArea( double diam ) {
    return this.pizzaArea(diam) + this.pizzaArea(12);
    }


  }