二叉搜索树查找指定的值

构造一个二叉搜索树，查找指定元素的值，代码案例如下：

#include <iostream>
using namespace std;

struct TreeNode {
    int data;
    TreeNode *left;
    TreeNode *right;

    TreeNode(int value):data(value), left(nullptr), right(nullptr){}
};

//向二叉搜索树插入节点
void insert(TreeNode *&root, int value)
{
    if (root == nullptr)
    {
        root = new TreeNode(value);
    }
    else if (value < root->data)
    {
        insert(root->left, value);
    }
    else
    {
        insert(root->right, value);
    }

}

//向二叉搜索树查找节点
TreeNode *search(TreeNode *root, int value)
{
    if (root == nullptr || root ->data == value)
    {
        return root;
    }

    if (value < root->data)
    {
        return search(root->left, value);
    }
    return search(root->right, value);
    
 
}

//中序遍历二叉搜索树 
void midTreefun(TreeNode *root)
{
    if (root == nullptr)
    {
        return;
    }

    midTreefun(root->left);
    
    cout << "root->data = " << root->data << ",";

    midTreefun(root->right);
}

int main()
{
    TreeNode *root = nullptr;

    insert(root, 2);
    insert(root, 3);
    insert(root, 4);
    insert(root, 5);
    insert(root, 6);
    insert(root, 7);
    insert(root, 8);
    insert(root, 9);

    cout << "begin mid tree" << endl;

    midTreefun(root);
    cout << endl;

    int value = 6;

    TreeNode *node = search(root, value);
    if (node != nullptr)
    {
        cout << "value = " << value << endl;
    }
    else
    {
        cout << "没找到该value值" << endl;
    }
    return 0;
}

//输出:
begin mid tree
root->data = 2,root->data = 3,root->data = 4,root->data = 5,root->data = 6,root->data = 7,root->data = 8,root->data = 9,     
value = 6