root.left用malloc分配地址了，为什么在pushDown()结束之后，root.left又没有初始化了

class Node {
public:
    int value;
    Node* left;
    Node* right;

    Node(int val) {
        value = val;
        left = nullptr;
        right = nullptr;
    }
};

void pushDown(Node* root) {
    root->left = new Node(10);
}

int main() {
    Node* root = new Node(5);

    pushDown(root);

    // 确保root.left被正确初始化
    if (root->left != nullptr) {
        // 打印初始化的值
        std::cout << root->left->value << std::endl;
    }

    // 释放内存
    delete root->left;
    delete root;

    return 0;
}