指针的传递并不是构造副本

#include <iostream>
#include <string>
#include <algorithm>
#include <cstring>
#include <stack>
using namespace std;

struct Node {
    char ch;
    int val;
    string code;
    Node* l;
    Node* r;
    Node (int wei,int index):ch('A'+index),val(wei),l(NULL),r(NULL),code(""){}
};


void f(Node* k) {
    k->val = 15;
}


int main() {
    stack<Node*> s;
    Node* tmp = new Node (23,0);
    s.push(tmp);
    cout<<s.top()->val<<" "<<s.top()->ch<<endl;
    tmp->val = 30;
    cout<<s.top()->val<<" "<<s.top()->ch<<endl;
    f(s.top());
    cout<<s.top()->val<<" "<<s.top()->ch<<endl;
}