C++ 二叉搜索树代码

#include <iostream>
using namespace std;template<typename T>
struct TreeNode{T val;TreeNode *left;TreeNode *right;TreeNode():val(0), left(NULL), right(NULL){}TreeNode(T x):val(x), left(NULL), right(NULL){}
};template<typename T>
class BinarySearchTree{
private:TreeNode<T> *root;TreeNode<T>* insertNode(TreeNode<T> *node, T value);TreeNode<T>* removeNode(TreeNode<T> *node, T value);bool searchNode(TreeNode<T> *node, T value);void inOrder(TreeNode<T> *node);
public:BinarySearchTree(): root(NULL){}~BinarySearchTree();void insert(T value){root = insertNode(root, value);}void remove(T value){root = removeNode(root, value);}bool search(T value){return searchNode(root, value);}void inOrderTraversal(){inOrder(root);cout << endl;}
};template<typename T>
BinarySearchTree<T>::~BinarySearchTree(){while(root){remove(root->val);}
}template<typename T>
TreeNode<T>* BinarySearchTree<T>::insertNode(TreeNode<T> *node, T value){if(node == NULL){return new TreeNode<T>(value);}if(value < node->val){node->left = insertNode(node->left, value);}else if(value > node->val){node->right = insertNode(node->right, value);}return node;
}template<typename T>
TreeNode<T>* BinarySearchTree<T>::removeNode(TreeNode<T> *node, T value){if(node == NULL){return NULL;}if(value < node->val){node->left = removeNode(node->left, value);}else if(value > node->val){node->right = removeNode(node->right, value);}else{if(node->left == NULL && node->right == NULL){delete node;return NULL;}else if(node->left == NULL){TreeNode<T> *rightChild = node->right;delete node;return rightChild;}else if(node->right == NULL){TreeNode<T> *leftChild = node->left;delete node;return leftChild;}else{TreeNode<T> *replacement = node->right;while(replacement->left){replacement = replacement->left;}node->val = replacement->val;node->right = removeNode(node->right,replacement->val);}}return node;
}template<typename T>
bool BinarySearchTree<T>::searchNode(TreeNode<T> *node, T value){if(node == NULL){return false;}if(value < node->val){return searchNode(node->left, value);}else if(value > node->val){return searchNode(node->right, value);}return true;
}template<typename T>
void BinarySearchTree<T>::inOrder(TreeNode<T> *node){if(node){inOrder(node->left);cout << node->val << ',';inOrder(node->right);}
}int main()
{BinarySearchTree<int> bst;bst.insert(50);bst.insert(40);bst.insert(60);bst.insert(80);bst.insert(90);bst.insert(10);bst.insert(20);bst.insert(30);bst.insert(70);bst.inOrderTraversal();cout << bst.search(9090) << endl;cout << bst.search(70) << endl;bst.remove(70);bst.inOrderTraversal();bst.insert(65);bst.inOrderTraversal();return 0;
}