编辑代码

public class halfFind {
    static int half(int[] arr, int index){
        int low = 0;
        int high = arr.length - 1;  //设置查找区间，注意数组下标从0开始
        int mid;
        while (low <= high) {   //当区间存在时
           
            mid = (low + high) / 2;

            if (index > arr[mid]){
                high = mid - 1;
            }
            else if (index < arr[mid]){
                low = mid + 1;
            }
            else return mid;  //查找成功，返回元素序号
        }
        return -1;  //查找失败，返回-1
    }

    public static void main(String[] args)
    {
        int arr[] = {85, 63, 52, 34, 25, 17, 6};
        System.out.println("6在数组中的下标是："+ half(arr, 6));
    }

}