编辑代码

public class HalfFind {
    public static void main(String[] args)
    {
        int r[]={7, 14, 18, 21, 23, 29, 31, 35, 38};
        int i=BinSearch1(r,9,18);
        System.out.println("在数组中的下标是："+i);
    }
 
    static int BinSearch1(int r[], int n, int k)
    {
        int low = 0, high = n - 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 (k < r[mid])	high = mid - 1;
            else	if (k > r[mid]) low = mid + 1;
            else return mid;                      //查找成功，返回元素序号
        }
        return 0;                                  //查找失败，返回0
    }
 
}