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  1. #include <iostream>
  2. #include <string>
  3. #include <vector>
  4. #include <map>
  5. #include <array>
  6. #include <iomanip>
  7. #include <set>
  8. #include <tuple>
  9. #include <algorithm>
  10. #include <vector>
  11. #include <bitset>
  12. #include <list>
  13. #include <fstream>
  14. #include <memory>
  15. #include <sstream>
  16. #include <chrono>
  17. #include <ctime>
  18. #include <iomanip>
  19. #include <locale>
  20. #include <cstring>
  21. #include <cmath>
  22. #include <complex>
  23. #include <queue>
  24. #include <cstdint>
  25. #include <random>
  26. #include <array>
  27. #include <typeinfo>
  28. #include <thread>
  29. #include <mutex>
  30. #include <cassert>
  31. #include <functional>
  32. #include <atomic>
  33. #include <future>
  34. #include <tuple>
  35. #include <iterator>
  36. #include <unordered_map>
  37. #include <deque>
  38.  
  39. using namespace std;
  40.  
  41.  
  42.  
  43. class A
  44. {
  45. protected:
  46.     int m_X;
  47. public:
  48.     A() { 
  49.         std::cout << "in A ctor" << std::endl; 
  50.         m_X = 0;
  51.     }
  52.     virtual void printX(){ std::cout << "in A " << m_X << std::endl; }
  53. };
  54.  
  55. class B : public A
  56. {
  57. public:
  58.     B() {
  59.         std::cout << "in B ctor" << std::endl; 
  60.         m_X = 1;
  61.     }
  62.     virtual void printX(){ std::cout << "in B " << m_X << std::endl; }
  63. };
  64.  
  65. class As
  66. {
  67. public:
  68.     void AddA(  A &a ){ m_As.push_back( std::ref(a) ); }
  69.     void PrintXs() const
  70.     {
  71.         for ( auto a : m_As )
  72.         {
  73.             a.get().printX();
  74.         }
  75.     }
  76. private:
  77.     std::vector<std::reference_wrapper<A>> m_As;
  78. };
  79.  
  80. int main()
  81. {
  82.     As as;
  83.     B b;
  84.     as.AddA( b );
  85.     as.PrintXs();
  86.     system("pause");
  87.     return 0;
  88. }
Success #stdin #stdout #stderr 0s 2988KB
comments (?)
stdin
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Standard input is empty
stdout
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in A ctor
in B ctor
in B 1
stderr
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sh: pause: not found
https://ideone.com/rkidCg
language:
C++14 (gcc 8.3)
created:
12 years ago
visibility:
public

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