Java增强循环

Question

请逐步解释一下这段代码的输出:

public class My {
    public static void main(String[] args) {
        int[] a = {1,2,3,4,1};
        for (int n : a) {
            a[n] = 0;
        }
        for (int n : a) {
            System.out.println(n);
        }
    }
}

我知道这是一个增强循环。但不明白它如何与 a[n]=0 一起使用 为什么这段代码输出00301？

Answer 1

您可以通过添加 println 语句来调试它:

    for (int n : a) {
        System.out.println("Changing element " + n + " of array from " + a[n] + " to 0");
        a[n] = 0;
    }

其输出是:

Changing element 1 of array from 2 to 0
Changing element 0 of array from 1 to 0
Changing element 3 of array from 4 to 0
Changing element 0 of array from 0 to 0
Changing element 1 of array from 0 to 0