/**
* A Simple PriceCalculator  - using a "special value" to indicate error occurrence
*
* @author Professor David Bernstein, James Madison University
* version 1.0
* @author Professor Elizabeth Adams, James Madison University
* version 1.1
*/
public class PriceCalculator
{
 private double[] discounts = {0., 1.,  5., 20., 100.};
 
 public double applyDiscount (double price, int quantity)
 {
   double  	discountedPrice;
	int		i;

	discountedPrice = price;
	
	i = discounts.length-1;
	
	while (i >= 0)
	{
	   if (quantity >= i)
		{
		   discountedPrice = price - discounts[i];
		}
		i--;
   }
	if (discountedPrice < 0)
	  discountedPrice = -1; // special value to handle an invalid price
	return discountedPrice;
 }
}