//*******************************************************************
//   Recurse4.java
//*******************************************************************

public class Recurse4
{
   public static int BinSearch( int x, int[] A, int low, int high )
   {
       int middle, mySol;

       if ( low > high )
       {
          /* ------------------------------------------------------
	     Solve the base case:
	     ------------------------------------------------------ */
          return( -1 );        // Not found
       }
       else
       {
          /* ------------------------------------------------
	     Solve a non-trivial binary search
             ------------------------------------------------ */

          middle = (low + high)/2;

          if ( x == A[middle] )
          {
             mySol = middle;           // Found at array element index "middle"
          }
          else if ( x < A[middle] )
          {
             mySol = BinSearch( x, A, low, middle-1 );  // smaller problem
          }
	  else  //  x > A[middle]
          {
             mySol = BinSearch( x, A, middle+1, high );  // smaller problem     
          }

	  return ( mySol );
       }
   }

   public static void main (String[] args)
   {
      int[] A = {1, 4, 6, 9, 12, 15, 18, 21, 23, 27, 31, 33};

      int r;

      r = BinSearch( 27, A, 0, A.length);
      System.out.println("Find 27: " + r);

      r = BinSearch( 28, A, 0, A.length);
      System.out.println("\nFind 28: " + r);

   }
}