stockitem.java

北京大学出版社的

package questions.c5;
class Identifiable {
   private int idNum =  -1;
   public Identifiable( int id ) {
      idNum = id;
   }
   public void setID( int id ) {
      idNum = id;
   }
}
public class StockItem extends Identifiable {
   private double price = 0.00;
   public void setPrice( double p ) {
      price = p;
   }
   public static void main( String[] args ) {
      StockItem s = new StockItem();
      s.setID( 12343567 );
      s.setPrice( 34.67 );
   }
}