boolean binsearch(String s)
{
   int left, right, middle;
   String sm;

   left = 0;
   right = v.size();
   while (left <= right)
   {
      middle = (left + right) / 2;
      sm = (String)v.elementAT(middle);
      if (sm.compareTo(s) < 0)
         left = middle + 1;  // search the second half
      else if (sm.compareTo(s) > 0)
         right = middle - 1; // search the first half
      else
         return true;  // found it
   } //
   return false; // not found
}