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 + "在數組中的下標是  " + index);

 }
}