获取子树

Question

我有一个家庭作业，要创建一个二进制搜索树类及其一些方法。现在，我被困在获取子树上。

这是我的节点类

template <typename T> //Node class
class Node {
    T data;
    Node<T> *left, *right;
public:
    Node() {
        left = right = nullptr;
    };
    T getData() {
        return data;
    }
    void changeData(T newData);
    void push(Node<T> *&root, T data);
    void print(Node<T> *&root);
    void cleanMemory(Node<T> *&root);
    void map(Node<T> *&root, void (*f)(Node<T> *&root));
    void deleteNode(Node<T> *&root, T key);
    Node<T>* getSubTree(Node<T> *&root, T key);
    void assembleTree(Node<T> *&var, Node<T> *&root, T Key);
};

和子树方法

template <typename T>
void Node<T>::assembleTree(Node<T> *&var, Node<T> *&root, T key) {
    if (root != nullptr) {
        if (root->data == key) {
            var = root;
        }
        else {
            var->assembleTree(var, root->right, key);
            var->assembleTree(var, root->left, key);
        }
    }
}

template <typename T>
Node<T>* Node<T>::getSubTree(Node<T> *&root, T key) {
    Node<T> *var = nullptr;
    var->assembleTree(var, root, key);
    return var;
}

问题出在我的程序清除内存时。控制台每次都会这样写：

Studying (lab3)(14723,0x1000b75c0) malloc: *** error for object 0x100503050: pointer being freed was not allocated
Studying (lab3)(14723,0x1000b75c0) malloc: *** set a breakpoint in malloc_error_break to debug

我要清除内存的代码：

template <typename T>
void Node<T>::cleanMemory(Node<T> *&root) {
    if (root != nullptr) {
        root->right->cleanMemory(root->right);
        root->left->cleanMemory(root->left);
        delete root;
        root = nullptr;
    }
}

删除“ root = nullptr”后，出现“线程1：EXC_BAD_ACCESS（code = EXC_I386_GPFLT）”错误