/**
 * Find the subscript of the largest entry.  Used by selSort()
 */
   static int maxIdx ( Comparable[] x, int n )
   {  int big = 0,    // Subscript of largest encountered
          k;          // Loop variable

      for ( k = 1; k < n; k++ ) // Start at 1 --- no need to check 0
         if ( x[big].compareTo(x[k]) < 0 )   // I.e., NOT the biggest so far
            big = k;
      return big;
   } // end maxIdx()

/**
 * Swap two array entries.  Used by selSort()
 */
   static void swap ( Comparable[] x, int p, int q )
   {  Comparable t = x[p];  x[p] = x[q];  x[q] = t;  }

/**
 * Recursive selection sort --- NOT the recommended formulation ! ! !
 */
   static void selSort ( Comparable[] x, int size )
   {  if ( size > 1 )
      {  int j = maxIdx ( x, size ); // Subscript of largest entry

         swap ( x, size-1, j );      // Move to end of the array
         selSort ( x, size-1 );      // Recursively sort the front end
                                     // NOTE:  tail recursion, easy optim.
      } // end if ( size > 1 )
   // else is ignored --- array of 0 or 1 entries is already sorted
   } // end selSort()