public class HalfSearch {  public static int halfSearch(int a[], int x) {   int mid, left, right;   left = 0;   right = a.length - 1;    mid = (left + right) / 2;   while (a[mid] != x) {    if (x > a[mid]) {     left = mid + 1;    }    else if (x < a[mid]) {     right = mid - 1;    }             mid=(left+right)/2;   }   return mid;  }  public static void main(String[] args) {   int a[] = { 1, 2, 3, 4, 5, 6,7,8,9,10 };   for (int i = 0; i < a.length; i++) {    System.out.print(a[i] + "  ");   }   System.out.println();   int s = 10;   int index = halfSearch(a, s);   System.out.println(s + "在数组中的下标是  " + index);  } }