Binary Search(Java)(递归)

 1 public static int rank(int[] array, int k, int front, int rear)
 2 {
 3     if(front > rear)
 4         return -1;
 5         
 6     int mid = front + (rear - front) / 2;
 7     if(k == array[mid])
 8         return mid;
 9     else if(k > array[mid])
10         return rank(array, k, mid + 1, rear);
11     else 
12         return rank(array, k, front, mid - 1);
13 }