請定義一個交通工具(Vehicle)的類，其中有: 屬性：速度(speed)，體積(size)等等

 1 public class Vehicle {  2     double speed;  3     double size;  4  Vehicle(){  5         speed=1.0;  6         size=2.0;  7  }  8     void move(){  9  } 10     void setSpeed(int speed){ 11         this.speed=speed; 12  } 13     void setSize(int size){ 14         this.size=size; 15  } 16     void speedUp(){ 17         speed=speed+1; 18         System.out.println("汽車加速後的速度爲"+speed+"公里/時"); 19  } 20     void speedDown(){ 21         speed=speed-1; 22         System.out.println("汽車減速後的速度爲"+speed+"公里/時"); 23  } 24 } 25 --------------------------------------------------------------------------------
26 public class Test { 27 
28     public static void main(String[] args) { 29         // TODO Auto-generated method stub
30         Vehicle aaa=new Vehicle(); 31         System.out.println("汽車的速度爲"+aaa.speed+"公里/時"); 32         System.out.println("汽車的體積爲"+aaa.size+"立方米"); 33  aaa.speedUp(); 34  aaa.speedDown(); 35  } 36 
37 }