SCJP題庫第109題
Given:
5. class Payload{
6. private int weight;
7. public Payload (int w){weight = w;}
8. public void setWeight(int w){weight = w;}
9. public String toString(){return Integer.toString(weight);}
10. }
11. public class TestPayload{
12. static void changePayload(Payload p){/* insert code */}
13. public static void main(String[] args){
14. Payload p = new Payload(200);
15. p.setWeight(1024);
16. changePayload(p);
17. System.out.println("p is " + p);
18. }}
Which code fragment, inserted at the end of line 12, produces the output p is 420?
A. p.setWeight(420);
B. p.changePayload(420);
C. p = new Payload(420);
D. Payload.setWeight(420);
E. p = Payload.setWeight(420);
Ans: A
解說:
此題P物件以字串的表現請看第15行的toString方法，此方法輸出物件中的屬性weight，因此，為了要使P輸出420，第20行中必須用setWeight方法設定weight值為420
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