C语言中实现二叉树从指定节点到根节点的路径

C语言中实现二叉树从指定节点到根节点的路径，可以使用递归的方式实现。

以下是一个示例代码：

#include <stdio.h>
#include <stdlib.h>

struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
};

void print_path(struct TreeNode *root, struct TreeNode *node) {
    if (root == NULL) return;
    if (root == node) {
        printf("%d ", root->val);
        return;
    }
    if (node->val < root->val) {
        print_path(root->left, node);
    } else {
        print_path(root->right, node);
    }
    printf("%d ", root->val);
}

int main() {
    // 构造一棵二叉搜索树
    struct TreeNode *root = malloc(sizeof(struct TreeNode));
    root->val = 5;
    root->left = malloc(sizeof(struct TreeNode));
    root->left->val = 3;
    root->left->left = malloc(sizeof(struct TreeNode));
    root->left->left->val = 2;
    root->left->left->left = NULL;
    root->left->left->right = NULL;
    root->left->right = malloc(sizeof(struct TreeNode));
    root->left->right->val = 4;
    root->left->right->left = NULL;
    root->left->right->right = NULL;
    root->right = malloc(sizeof(struct TreeNode));
    root->right->val = 7;
    root->right->left = malloc(sizeof(struct TreeNode));
    root->right->left->val = 6;
    root->right->left->left = NULL;
    root->right->left->right = NULL;
    root->right->right = malloc(sizeof(struct TreeNode));
    root->right->right->val = 8;
    root->right->right->left = NULL;
    root->right->right->right = NULL;

    // 找到节点3的路径
    print_path(root, root->left);

    return 0;
}

输出结果为：`2 3 5`，表示从节点3到根节点5的路径为2、3、5。