public void quickSort(int array[], int start, int end)
   {
      int pivotPoint;
      
      if (start < end)
      {
         // Get the pivot point.
         pivotPoint = partition(array, start, end);
         
         // Sort the first sub list.
         quickSort(array, start, pivotPoint - 1);
         
         // Sort the second sub list.
         quickSort(array, pivotPoint + 1, end);
      }
   }