1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:

int BinarySearch(int A[1...n], int y, int low, int high) { 
 if (high < low) {
    return -1; //not found 
 }
 mid = low + (high - low) / 2; 
 if (A[mid] > y) {
    return BinarySearch(A, y, low, mid-1); 
 }
 else if (A[mid] < y) {
       return BinarySearch(A, y, mid+1, high); 
 }
 else {
      return mid; //found 
}
}