JAVA 範例 ch10 Sample7

變更物件的內容

/*變更物件的內容*/
class Car
{
 private int num;
 private double gas;
 
 public Car()
 {
  num=0;
  gas=0.0;
  System.out.println("生產了車子。");
 }
 public void setCar(int n,double g)
 {
  num=n;
  gas=g;
  System.out.println("將車號設為" + num + "汽油量設為" + gas + "。");
 }
 public void show()
 {
  System.out.println("車號是" + num + "。");
  System.out.println("汽油量是" + gas + "。");
 }
}

class Sample7
{
 public static void main(String[] args)
 {
  Car car1;
  System.out.println("宣告car1。");
  car1=new Car();
  car1.setCar(1234,20.5);
  
  Car car2;
  System.out.println("宣告car2。");
  
  car2=car1;
  System.out.println("將car1指定給car2。");
  
  System.out.print("car1的");
  car1.show();
  System.out.print("car2的");
  car2.show();
  
  System.out.println("改變car1的相關資料。");
  car1.setCar(2345,30.5);   //使用car1來變更物件
  
  System.out.print("car1的");
  car1.show();
  System.out.print("car2的");
  car2.show();
 }
}