Question

我目前只能执行一项任务，在该任务中，我必须反转数组中元素的顺序。但是问题是我只能得到10 10次而不是10 9 8 ...

package JavaSection4;

public class Assignment4Nr2 {

    public static void main(String[] args) {        

        int[] ranNum = new int[10];

        ranNum[0] = 1;
        ranNum[1] = 2;
        ranNum[2] = 3;
        ranNum[3] = 4;
        ranNum[4] = 5;
        ranNum[5] = 6;
        ranNum[6] = 7;
        ranNum[7] = 8;
        ranNum[8] = 9;
        ranNum[9] = 10;     

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

            int l = 0;

            l = ranNum.length - 1;

            System.out.println(ranNum[l]);      
        }       
    }
}

Answer 1

您没有撤销订单，只是尝试从头开始阅读。

要取消顺序

Integer[] integers = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
ArrayUtils.reverse(integers);

使用适当的工具（在本例中为apache-commons）。通过查看工具源代码，很容易发现它是如何完成的：

public static void reverse(Object[] array) {
    if (array == null) {
        return;
    }
    int i = 0;
    int j = array.length - 1;
    Object tmp;
    while (j > i) {
        tmp = array[j];
        array[j] = array[i];
        array[i] = tmp;
        j--;
        i++;
    }
}

Answer 2

public class ReverseArray {  
public static void main(String[] args) {  
    //Initialize array  
    int [] arr = new int [] {1, 2, 3, 4, 5};  
    System.out.println("Original array: ");  
    for (int i = 0; i < arr.length; i++) {  
        System.out.print(arr[i] + " ");  
    }  
    System.out.println();  
    System.out.println("Array in reverse order: ");  
    //Loop through the array in reverse order  
    for (int i = arr.length-1; i >= 0; i--) {  
        System.out.print(arr[i] + " ");  
    }  
}

}

应该可以解决问题。

反转数组中元素的顺序

2 个答案: