Question

为什么这段代码不会为数组的值添加“1”？（我用“Enhanced For Loop”编写了它;当我用“old For”编写它时，它起作用了。

public class EnhanceForLoop {
    public static void main(String[] args) {

            int[] list = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};

            System.out.println("List before call addOne");
            printList(list);

            System.out.println("Calling addOne");
            addOne(list);

            System.out.println("List after call addOne");
            printList(list);
    }               

    public static void addOne(int[] list) {
        for (int val : list) {
            val = val + 1;
        }
    }

    public static void printList(int[] list) {
        System.out.println("index, value");
        for (int i = 0; i < list.length; i++) {
            System.out.println(i + ", " + list[i]);
        }
    }
}

Answer 1

您没有增加数组值。

public static void addOne(int[] list){
     for(int i=0;i<list.length;i++){
                list[i] = list[i] + 1;
         }
}

声明

val = val + 1;   //will not increase array value it will increase val value

Answer 2

您增加的值是声明的变量val，它是数组当前迭代索引变量的断开副本。

在Java中增加Array的值

2 个答案: