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  1. #include <iostream>
  2. #include <memory>
  3. #include <type_traits>
  4.  
  5. template <typename T>
  6. void deduce_type()
  7. {}
  8.  
  9.  
  10. class any
  11. {
  12.     /*
  13.     template <typename T, typename ... Args>
  14.     any(Args&& ... args)
  15.         : ptr_(new T(std::forward<Args>(args) ...), std::default_delete<T>())
  16.     {}
  17.     */
  18.  
  19. public:
  20.  
  21.     template <typename T>
  22.     any(T&& other)
  23.         : ptr_(new T(std::forward<T>(other))),
  24.         deduce_type_(&deduce_type<T>)
  25.     {}
  26.  
  27.     template <typename T>
  28.     bool contains_type() const
  29.     {
  30.     	auto cc = deduce_type<T>;
  31.         return deduce_type_ == cc;
  32.     }
  33.  
  34. private:
  35.     // std::unique_ptr<void, std::default_delete<void>> ptr_;
  36.     void* ptr_;
  37.     void(*deduce_type_)();
  38.  
  39. };
  40.  
  41. struct Foo
  42. {
  43.  
  44. };
  45.  
  46.  
  47. int main()
  48. {
  49.  
  50.     any anyInt = 16;
  51.     any anyInt2 = 17;
  52.     any anyDouble = 2.0;
  53.     any anyFoo = Foo();
  54.  
  55.  
  56.     bool isInt = anyInt.contains_type<int>(),
  57.         isInt2 = anyInt2.contains_type<int>(),
  58.         notDouble = anyInt.contains_type<double>(), // 0 expected
  59.         isDouble = anyDouble.contains_type<double>(),
  60.         isFoo = anyFoo.contains_type<Foo>(),
  61.         notFoo = anyInt.contains_type<Foo>(); // 0 expected
  62.  
  63.     std::cout << "is int = " << isInt << std::endl;
  64.     std::cout << "is int = " << isInt2 << std::endl;
  65.     std::cout << "is not double = " << notDouble << std::endl;
  66.     std::cout << "is double = " << isDouble << std::endl;
  67.     std::cout << "is Foo = " << isFoo << std::endl;
  68.     std::cout << "is not Foo = " << notFoo << std::endl;
  69.  
  70.     return 0;
  71. }
Success #stdin #stdout 0s 4964KB
comments (?)
stdin
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Standard input is empty
stdout
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is int = 1
is int = 1
is not double = 0
is double = 1
is Foo = 1
is not Foo = 0
https://ideone.com/zUAlOy
language:
C++14 (gcc 8.3)
created:
4 years ago
visibility:
secret

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