parcel.java

Java程序设计(美) David D. Riley著 机械工业出版社 书籍配套 代码

//Figure 8.2

public class Parcel  {
	public double  weight;
	public double  volume;
	public boolean isAirFreight;

	/**	post:	weight==w  and  volume==v  and  isAirFreight==b  */
	public Parcel( double w, double v, boolean b)   {
		weight = w;
		volume = v;
		isAirFreight = b;
	}
	
	/**	post:		isAirFreight implies 
	 *                      result == cost to ship as air freight.
	 *				and  !isAirFreight implies 
	 *                      result == cost to ship by truck. */
	public  double  shippingCost()   {
		double  cost;
		if (isAirFreight)   
			if  (weight > 1.0) 
				cost = 15 + 2.75 * weight + 6 * (volume-1);
			else
				cost = 15 + weight * 2.75;
		else  // !isAirFreight
			cost = 5 + 0.04 * weight;
		return cost;
	}				
}