55. Given:
11. abstract class Vehicle{public int speed(){return 0；}}
12. class Car extends Vehicle{public int speed(){return 60；}}
13. class RaceCar extends Car{public int speed(){return 150；}}
...
21. RaceCar racer = new RaceCar()；
22. Car car = new RaceCar()；
23. Vehicle vehicle = new RaceCar()；
24. System.out.println(racer.speed() + ", " + car.speed()
25. + ", " + vehicle.speed())；
What is the result?
(A) 0, 0, 0
(B) 150, 60, 0
(C) Compilation fails.
(D) 150, 150, 150
(E) An exception is thrown at runtime.
阿摩線上測驗
登入