package Test;

 import java.util.Arrays;

 public class BinarySearch {

     public static void main(String[] args) {

         int [] a = {1,5,7,9,11,12,16,20};

         int target = 16;

         //System.out.println(Arrays.binarySearch(a, target));

         System.out.println(binarySearch(a, target));

     }

     public static int binarySearch(int [] a, int target){

         int low = 0;

         int high = a.length - 1;

         while (low <= high) {

             int mid = (low + high) >>> 1;

             int midVal = a[mid];

             if (midVal < target)

                 low = mid + 1;

             else if (midVal > target)

                 high = mid - 1;

             else

                 return mid; // key found

         }

         return -(low + 1);  // key not found.

     }

 }