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  1. #include <iostream>
  2. #include <vector>
  3. using namespace std;
  4.  
  5. class A {
  6. public:
  7.     int num = 0;
  8.     A* parent = nullptr;
  9.  
  10.     A(){ cout << "A created: " << this << endl; }
  11.  
  12.     A(const A &s) : num(s.num), parent(s.parent)
  13.     {
  14.     	cout << "A copied: " << &s << " -> " << this << endl;
  15.     }
  16.  
  17.     ~A(){ cout << "A destroyed: " << this << endl; }
  18.  
  19.     vector<A> foo(A &a)
  20.     {
  21.         A a1;
  22.         a1.num = a.num;
  23.         a1.parent = &a;
  24.  
  25.         vector<A> list;
  26.         list.reserve(1);
  27.         list.push_back(a1);
  28.  
  29.         A &temp = list.front();
  30.  
  31.         cout << "(foo) temp.parent: " << temp.parent << ", num: " << temp.parent->num << endl;
  32.  
  33.         return list;
  34.     }
  35. }; 
  36.  
  37. int main()
  38. {
  39.     A a; 
  40.     a.num = 2;
  41.  
  42.     vector<A> list = a.foo(a);
  43.  
  44.     A &temp = list.front();
  45.  
  46. 	cout << "(main) temp.parent: " << temp.parent << ", num: " << temp.parent->num << endl;
  47.  
  48.     return 0;
  49. }
Success #stdin #stdout 0.01s 5388KB
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stdin
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Standard input is empty
stdout
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A created: 0x7ffd7319e8b0
A created: 0x7ffd7319e850
A copied: 0x7ffd7319e850 -> 0x556ccff0fe80
(foo) temp.parent: 0x7ffd7319e8b0, num: 2
A destroyed: 0x7ffd7319e850
(main) temp.parent: 0x7ffd7319e8b0, num: 2
A destroyed: 0x556ccff0fe80
A destroyed: 0x7ffd7319e8b0
https://ideone.com/6kSXs6
language:
C++ (gcc 8.3)
created:
3 years ago
visibility:
secret

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