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  1. #include <functional>
  2. #include <iostream>
  3.  
  4. class Foo final
  5. {
  6. public:
  7. 	Foo() { std::cout << "Default constructor" << std::endl; }
  8. 	Foo(const Foo&) { std::cout << "Copy constructor" << std::endl; }
  9. 	Foo(Foo&&) noexcept { std::cout << "Move constructor" << std::endl; }
  10.  
  11. 	Foo& operator=(const Foo&)
  12. 	{
  13. 		std::cout << "Copy assignment" << std::endl;
  14.  
  15. 		return *this;
  16. 	}
  17.  
  18. 	Foo& operator=(Foo&&) noexcept
  19. 	{
  20. 		std::cout << "Move assignment" << std::endl;
  21.  
  22. 		return *this;
  23. 	}
  24.  
  25. 	std::function<void()> f() const noexcept
  26. 	{
  27. 		return [*this]{ g(); };
  28. 	}
  29.  
  30. 	~Foo() noexcept
  31. 	{
  32. 		std::cout << "Destructor" << std::endl;
  33. 	}
  34.  
  35. private:
  36. 	void g() const noexcept
  37. 	{
  38. 		std::cout << "Hello, World! :-)" << std::endl;
  39. 	}
  40. };
  41.  
  42. void f(std::function<void()> cb) noexcept
  43. {
  44. 	if (cb)
  45. 	{
  46. 		cb();
  47. 	}
  48. }
  49.  
  50. int main()
  51. {
  52. 	std::function<void()> cb;
  53.  
  54. 	std::cout << '1' << std::endl;
  55. 	{
  56. 		Foo foo;
  57. 		std::cout << '2' << std::endl;
  58. 		cb = foo.f();
  59. 		std::cout << '3' << std::endl;
  60. 	}
  61.  
  62. 	std::cout << '4' << std::endl;
  63. 	f(std::move(cb));
  64. 	std::cout << '5' << std::endl;
  65.  
  66. 	return 0;
  67. }
Success #stdin #stdout 0.01s 5288KB
comments (?)
stdin
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Standard input is empty
stdout
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1
Default constructor
2
Copy constructor
Copy constructor
Destructor
3
Destructor
4
Hello, World! :-)
Destructor
5
https://ideone.com/ThCFlH
language:
C++14 (gcc 8.3)
created:
14 hours ago
visibility:
public

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