template + recursion

template <typename Data>
class AVLTree {
public:
    class Node;
private:
    typename AVLTree<Data>::Node* root;
    int size;
public:
    AVLTree();
    ~AVLTree();
    bool find(Data& data) const;
    AVLStatus add(Data& data);
    AVLStatus remove(Data& data);
    int getSize();
    Data AVLgetNext(Data data);
    Data AVLgetPrev(Data data);
    void printPreOrder() const;
    void printInOrder() const;
    void printPostOrder() const;
};

template <typename Data>
void destroyTree(typename AVLTree<Data>::Node* element) {
    if(!element) {
        return;
    }
    destroyTree<Data>(element->getLeft());
    destroyTree<Data>(element->getRight());
    delete element;
}

template <typename Data>
AVLTree<Data>::~AVLTree() {
    destroyTree<Data>(root);
    root = 0;
}

and I call it from here:

using namespace Data_Structures;

int main() {
    AVLTree<int> test = AVLTree<int>();
    return 0;
}