Java - 方法的输出

Question

查看这个特定方法的输出让我感到困惑。我试图准确地理解它在做什么。

方法是这样的:

for (int i = 0; i < 4; i ++) {
    for (int j = 0; j < 9; j++) {
    if (j==5) {
        break;
    }
    if ((j==0) || (i==0)) {
        continue;
    }
    if (!((j*i % 3) != 0)) {
    System.out.println(j*i);
    }
}

}

我知道输出是什么，但我仍然不确定它是如何工作的，这就是我在这里问的原因。因此，该方法将遍历 j 直到达到 5，然后中断。

然后它递增 i，j 为 0。 J != 5 所以它不会中断，j == 0 所以继续但随后 J 变为 3，而 I 变为 1。这就是我迷失的地方。 3从哪里来的？

我用它来打印幕后发生的事情

    public static void tester() {
    for (int i = 0; i < 4; i ++) {
        for (int j = 0; j < 9; j++) {
            if (j==5) {
                System.out.println("j == 5, breaking");
                break;
            }
            if ((j==0) || (i==0)) {
                System.out.println("J is " + j);
                System.out.println("I is " + i);
                System.out.println("j or i == 0, continuing");
                continue;
            }
            if (!((j*i % 3) != 0)) {
                System.out.println("J is " + j);
                System.out.println("I is " + i);
                System.out.println(j*i);
            }
        }
        System.out.println();
    }
}

输出如下:

J is 0

I is 0

j or i == 0, continuing

J is 1

I is 0

j or i == 0, continuing

J is 2

I is 0

j or i == 0, continuing

J is 3

I is 0

j or i == 0, continuing

J is 4

I is 0

j or i == 0, continuing

j == 5, breaking


J is 0

I is 1

j or i == 0, continuing

J is 3

I is 1

3

j == 5, breaking


J is 0

I is 2

j or i == 0, continuing

J is 3

I is 2

6

j == 5, breaking


J is 0

I is 3


j or i == 0, continuing

J is 1

I is 3

3

J is 2

I is 3

6

J is 3

I is 3

9

J is 4

I is 3

12

j == 5, breaking

Answer 1

3(以及后来的6)是从这段代码中出现的......

        if (!((j*i % 3) != 0)) {
            System.out.println("J is " + j);
            System.out.println("I is " + i);
            System.out.println(j*i);
        }

实际上，!((j*i % 3) != 0) 所说的是，当 j*i/3 的余数为 0 时，它运行此 if 语句中的代码。换句话说，只要 j*i 是 3 的倍数(3, 6、9、12)

逻辑很难理解 - 最好这样写......

        if ((j*i % 3) == 0) {
            System.out.println("J is " + j);
            System.out.println("I is " + i);
            System.out.println(j*i);
        }

在原来的方式中，所有的 ! 符号和多个方括号/大括号使得阅读变得困难。