template <class bstdata>
BST<bstdata>::BST():root(NULL){};

template <class bstdata>
BST<bstdata>::~BST(){
    destructorHelper(root);
}


template<class bstdata>
void BST<bstdata>::destructorHelper(NodePtr root)
{
    if(!root->left)
        destructorHelper(root->left);
    if(!root->right)
        destructorHelper(root->right);
    if(root!=NULL)
        delete root;
}
template <class bstdata>
bool BST<bstdata>::isEmpty()
{
    if(root==NULL)
        return true;
    else
        return false;
}