试图返回数组中某个元素的位置，打印时遇到问题

Question

我正在处理此代码以打印此数组中的位置，并且我认为在获取返回值时我的所有代码都是正确的，但是我无法获取任何值；打印在屏幕上。我尝试调用 arrayLength 方法进行打印，但我得到的只是错误“arrayLength 无法解析为变量”。所以我不确定要打印什么变量。

 public class Generics {

        static List<Integer> list = new ArrayList<Integer>();

        Integer[] array = {2, 4, 6, 8};

        Integer s= list.get(0);

         int arrayLength(int[] array, int value) {

        for (int i = 0; i < array.length; i++) {

            if(array[i]==value) {

                return i;

            }

        }

        return -1;

        }

        public static void main(String[] args) {

           System.out.println(arrayLength);

        }

      }

Answer 1

我相信您正在尝试打印函数而不是返回值。如果System.out.println(arrayLength);用System.out.println(arrayLength(array, 4));&nbsp;它替换应该打印数组中的索引 4同样如评论中所述，arrayLength 方法需要是静态的才能从 main 方法中调用

Answer 2

注意：整数 s= list.get(0); 给出 IndexOutOfBoundsException 因为列表是空的所以不可能检索第一个元素public class Generics {&nbsp; &nbsp; &nbsp; &nbsp; static int[] array = {2, 4, 6, 8};&nbsp; &nbsp; &nbsp; &nbsp; static int arrayLength(int[] array, int value) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; for (int i = 0; i < array.length; i++) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if(array[i]==value) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return i;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return -1;&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; public static void main(String[] args) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; System.out.println(arrayLength(array, 2));&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; System.out.println(arrayLength(array, 4));&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; System.out.println(arrayLength(array, 6));&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; System.out.println(arrayLength(array, 8));&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; }