从方法修改指针指针字段

#include <iostream>

struct Node {
    int data;
    Node* next;
};

void updatePointer(Node** ptr) {
    Node* newNode = new Node;
    newNode->data = 10;
    newNode->next = nullptr;
    *ptr = newNode;
}

int main() {
    Node* head = new Node;
    head->data = 5;
    head->next = nullptr;

    std::cout << "Before update: " << head->data << std::endl;
    updatePointer(&head);
    std::cout << "After update: " << head->data << std::endl;

    delete head; // Remember to free memory

    return 0;
}