关于“交换数据”的问题

public class Main {
    public static void main(String[] args) {
        int []arr = {1,2,3,4,5};
        for (int i = 0 , int j = arr.length - 1 ; i < j ; i++,j--){
            int temp =arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
        }
        for (int i = 0; i < arr.length; i++) {
            System.out.println(arr[i]);
        }
    }
}

哪里有问题？看了半天没看出来

在for循环的定义中，应该将int关键字去掉，只声明一次即可：for (int i = 0 , j = arr.length - 1; i < j; i++,j--) {...}