void bst::recInsert(string s, node * & r)
{
	if( r == NULL )  //base case: empty tree
	{
		r = new node;
		r->data = s;
		r->height = 0;
	}
	else if( s < r->data  ) //insert left
	{
		recInsert(s, r->left);

		if( height(r->left) - height(r->right) > 1 )
		{  //violation!
			//do some type of rotation
			else if( s < r->left->data )
				leftRotation(r);
			else //its a double
				doubleRotationLeft(r);
			if(s>r->data)
		}

		r->height = max( height(r->left), height(r->right) ) +1;
	}
	else//insert right, if greater or equal to root
	{
		recInsert(s, r->right);

		if( height(r->right) - height(r->left) > 1 )
		{
			if( s > r->right->data )
				rightRotation(r);
			else
				doubleRotationRight(r);
		}

		r->height = max( height(r->left), height(r->right) ) +1;
	}
}