#include <iostream>
#include <vector>
using namespace std;
 
class A {
public:
    int num = 0;
    A* parent = nullptr;
 
    A(){ cout << "A created: " << this << endl; }
 
    A(const A &s) : num(s.num), parent(s.parent)
    {
    	cout << "A copied: " << &s << " -> " << this << endl;
    }
 
    ~A(){ cout << "A destroyed: " << this << endl; }
 
    vector<A> foo(A a)
    {
        A a1;
        a1.num = a.num;
        a1.parent = &a;
 
        vector<A> list;
        list.reserve(1);
        list.push_back(a1);
 
        A temp = list.front();
 
        cout << "(foo) temp.parent: " << temp.parent << ", num: " << temp.parent->num << endl;
 
        return list;
    }
}; 
 
int main()
{
    A a; 
    a.num = 2;
 
    vector<A> list = a.foo(a);
 
    A temp = list.front();
 
	cout << "(main) temp.parent: " << temp.parent << ", num: " << temp.parent->num << endl;
 
    return 0;
}

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