template <class Comparable>BST;

template <class Comparable>
class BinaryNode
{
  private:
    Comparble   element;
    BinaryNode *left;
    BinaryNode *right;

    BinaryNode (const Comparable & theElement,
                const BinaryNode *L,
                const BinaryBode *R)
      : element (theElement), left(L), right(R)
   { /* no code */ }

   friend class BST<Comparable>
};