RedBlackNode( const Comparable & theElement = Comparable( ), RedBlackNode *lt = NULL, RedBlackNode *rt = NULL, int c = BLACK ) : element( theElement ), left( lt ), right( rt ), color( c ) { }
BinaryNode(const Comparable &x= Comparable(),BinaryNode *lt = NULL,BinaryNode* rt=NULL):element(x),left(lt),right(rt){}