c++二叉树

好的，下面是一个简单的 C++ 二叉树的实现：

#include <iostream>

using namespace std;

struct TreeNode {
    int val;
    TreeNode* left;
    TreeNode* right;
    TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

class BinaryTree {
private:
    TreeNode* root;

public:
    BinaryTree() {
        root = NULL;
    }

    void insert(int val) {
        TreeNode* newNode = new TreeNode(val);
        if (root == NULL) {
            root = newNode;
            return;
        }

        TreeNode* curr = root;
        while (true) {
            if (val < curr->val) {
                if (curr->left == NULL) {
                    curr->left = newNode;
                    return;
                }
                curr = curr->left;
            } else {
                if (curr->right == NULL) {
                    curr->right = newNode;
                    return;
                }
                curr = curr->right;
            }
        }
    }

    void inorderTraversal(TreeNode* node) {
        if (node == NULL) {
            return;
        }
        inorderTraversal(node->left);
        cout << node->val << " ";
        inorderTraversal(node->right);
    }

    void inorderTraversal() {
        inorderTraversal(root);
    }

    void preorderTraversal(TreeNode* node) {
        if (node == NULL) {
            return;
        }
        cout << node->val << " ";
        preorderTraversal(node->left);
        preorderTraversal(node->right);
    }

    void preorderTraversal() {
        preorderTraversal(root);
    }

    void postorderTraversal(TreeNode* node) {
        if (node == NULL) {
            return;
        }
        postorderTraversal(node->left);
        postorderTraversal(node->right);
        cout << node->val << " ";
    }

    void postorderTraversal() {
        postorderTraversal(root);
    }
};

int main() {
    BinaryTree tree;
    tree.insert(5);
    tree.insert(3);
    tree.insert(7);
    tree.insert(1);
    tree.insert(9);

    cout << "Inorder Traversal: ";
    tree.inorderTraversal();
    cout << endl;

    cout << "Preorder Traversal: ";
    tree.preorderTraversal();
    cout << endl;

    cout << "Postorder Traversal: ";
    tree.postorderTraversal();
    cout << endl;

    return 0;
}

这个二叉树实现了插入节点、中序遍历、前序遍历和后序遍历等基本操作。你可以根据需要进行修改和扩展。