SCJP程序给出输出8 2如何?

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);
    }
}

I tried this scjp piece of code and I am getting the output 5 3 can anyone tell me where i am going wrong

我尝试了这个scjp代码，我得到了输出5 3，谁能告诉我哪里出错了。

1 个解决方案

#1

The loop executes 5 times (z from 0 to 4)

循环执行5次(z从0到4)

In the if condition, ++x is evaluated all five times. But ++y is evaluated only when first part of condition is false.

在if条件下，所有5次都对+x进行评估。但是，只有当条件的第一部分为假时，才计算++y。

i.e., This condition:

即。这个条件:

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

becomes:

就变成:

//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

So finally, we have:

最后,我们有:

x = 8 and y = 2

Remember: ++x is pre-increment (think change-and-use) while x++ is post-increment(think use-and-change)

记住:++x是预增量(想想转换和使用)，而x++是后增量(想想使用和改变)

#1