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  1. #include <iostream>
  2. #include <type_traits>
  3.  
  4. template<typename Derived>
  5. struct base
  6. {
  7.     void const_method() const
  8.     {
  9.         static_cast<Derived*>(this)->method();
  10.     }
  11.  
  12.     void fixed_const_method() const
  13.     {
  14.         static_cast<
  15.             typename std::conditional<
  16.                 std::is_const<
  17.                     typename std::remove_pointer<decltype(this)>::type>::value,
  18.                 Derived const* const,
  19.                 Derived* const>::type>(this)->method();
  20.     }
  21. };
  22.  
  23. struct derived : public base<derived>
  24. {
  25.     void method() const
  26.     {
  27.         std::cout << "const method" << std::endl;
  28.     }
  29.  
  30.     void method()
  31.     {
  32.         std::cout << "non-const method" << std::endl;
  33.     }
  34. };
  35.  
  36. int main()
  37. {
  38.     derived d;
  39.     d.fixed_const_method();
  40.  
  41.     return 0;
  42. }
Success #stdin #stdout 0s 2852KB
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const method
https://ideone.com/52lFOM
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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