public int getLevel(String word)
{
   return getLevel(root, word);
}

/** Return level where the given word is stored (or should be added) in the
    tree rooted at the given node.
*/
private int getLevel(BinaryTreeNode<String> node, String word)
{
   if (node == null || node.item.equals(word))
   {
      return 1;
   }
   else if (word.compareTo(node.item) < 0) // word < node.item
   {
      return 1 + getLevel(node.leftChild, word);
   }
   else
   {
      return 1 + getLevel(node.rightChild, word);
   }
}