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  1. #include <iostream>
  2. #include <type_traits>
  3. #include <typeinfo>
  4.  
  5. template<typename Derived>
  6. struct base
  7. {
  8.     void const_method() const
  9.     {
  10.         static_cast<Derived*>(this)->method();
  11.     }
  12.  
  13.     void fixed_const_method() const
  14.     {
  15.         // base<derived> const*
  16.         std::cout << typeid(this).name() << std::endl;
  17.         // base<derived>
  18.         std::cout << typeid(typename std::remove_pointer<decltype(this)>::type).name() << std::endl;
  19.         // base<derived>
  20.         std::cout << typeid(decltype(*this)).name() << std::endl;
  21.         // derived const*
  22.         std::cout << typeid(typename std::conditional<
  23.                                 std::is_const<
  24.                                     typename std::remove_pointer<decltype(this)>::type>::value,
  25.                                 Derived const* const,
  26.                                 Derived* const>::type).name() << std::endl;
  27.  
  28.         static_cast<
  29.             typename std::conditional<
  30.                 std::is_const<
  31.                     typename std::remove_pointer<decltype(this)>::type>::value,
  32.                 Derived const* const,
  33.                 Derived* const>::type>(this)->method();
  34.     }
  35. };
  36.  
  37. struct derived : public base<derived>
  38. {
  39.     void method() const
  40.     {
  41.         std::cout << "const method" << std::endl;
  42.     }
  43.  
  44.     void method()
  45.     {
  46.         std::cout << "non-const method" << std::endl;
  47.     }
  48. };
  49.  
  50. int main()
  51. {
  52.     derived d;
  53.     d.fixed_const_method();
  54.  
  55.     return 0;
  56. }
Success #stdin #stdout 0s 2896KB
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PK4baseI7derivedE
4baseI7derivedE
4baseI7derivedE
PK7derived
const method
https://ideone.com/J9Tnq8
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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