SCJP程序输出8 2如何？

Question

class Foozit { 
    public static void main(String[] args) { 
     Integer x = 0; 
     Integer y = 0; 
     for (Short z = 0; z < 5; z++) { 
      if ((++x > 2) || ++y > 2) 
       x++; 
     } 
     System.out.println(x + "Hello World!" + y); 
    } 
} 

我想这SCJP一段代码和我得到的输出5 3谁能告诉我在哪里，我错了

Answer 1

循环执行5次（Z从0〜4）

在if条件，++ x全部评估五次。但++ y仅在条件的第一部分为假时才被评估。

即，这种情况：

if ((++x > 2) || ++y > 2) 

变为：

//1st iteration 
if(1 > 2 || 1 > 2) //False, x++ is not evaluated 

//2nd iteration 
if(2 > 2 || 2 > 2) //False, x++ is not evaluated 

//3rd iteration 
if(3 > 2 || 2 > 2) //True, the second ++y is skipped, but x++ is evaluated, x becomes 4 

//4th iteration 
if(5 > 2 || 2 > 2) //True, the second ++y is skipped, but x++ is evaluated, x becomes 6 

//5th iteration 
if(7 > 2 || 2 > 2) //True, the second ++y is skipped, but x++ is evaluated, x becomes 8 

所以最后，我们有：

x = 8 and y = 2 

记住：++ x是预增量（思变并且使用），而x ++是后增量（think use-and-change）