SCJP 1.6版考題 021

1. class Batman{
2.   int squares = 81;
3.   public static void main(String[] args){
4.     new Batman().go();
5.   }
6.   void go(){
7.     incr(++squares);
8.     System.out.println(squares);
9.   }
10. void incr(int squares){squares += 10;}
11. }


What is the result?

   A. 81
   B. 82
   C. 91
   D. 92
   E. Compilation fails.
   F. An exception is thrown at runtime. 

解答

---

Ans: B

解說:

go方法印出的squares是Batman的squares，incr所變更的squares是本身的方法變數
此是在考call by value觀念