Standard binary search function
int binarySearch ( int arr [ ] , int low , int high , int x ) { if ( high >= low ) { int mid = low + ( high - low ) / 2 ; if ( x == arr [ mid ] ) return mid ; if ( x > arr [ mid ] ) return binarySearch ( arr , ( mid + 1 ) , high , x ) ; else return binarySearch ( arr , low , ( mid - 1 ) , x ) ; } return -1 ; }