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  1. #include <iostream>
  2. #include <iostream>
  3. #include <math.h>
  4.  
  5. template< class T, class Op >
  6. struct Wrapper
  7. {
  8. 	Wrapper():t(nullptr){}
  9. 	Wrapper( T* ptrT ):t(ptrT){}
  10. 	Wrapper( Wrapper const& ) = default;
  11. 	Wrapper& operator=( Wrapper const& ) = default;
  12.  
  13. 	template<class...Args>
  14. 	auto operator()(Args&&...args) const->decltype( Op{}(std::declval<T*>(),std::declval<Args>()...)) {
  15. 		return Op{}(t, std::forward<Args>(args)...);
  16. 	}
  17. 	T* t;
  18. };
  19.  
  20. template< class T, bool isConst, class Sig >
  21. struct MemberFunc;
  22. template< class T, class R, class... Args >
  23. struct MemberFunc<T, false, R(Args...) > {
  24. 	template< R(T::*func)(Args...) >
  25. 	struct type {
  26. 		template<class... Ts>
  27. 		R operator()(T* t, Ts&&...ts) const {
  28. 			return (t->*func)(std::forward<Ts>(ts)...);
  29. 		}
  30. 	};
  31. };
  32. template< class T, class R, class... Args >
  33. struct MemberFunc<T, true, R(Args...) > {
  34. 	template< R(T::*func)(Args...) const >
  35. 	struct type {
  36. 		template<class... Ts>
  37. 		R operator()(T const* t, Ts&&...ts) const {
  38. 			return (t->*func)(std::forward<Ts>(ts)...);
  39. 		}
  40. 	};
  41. };
  42.  
  43. struct kernel
  44. {
  45.   double gauss( double s )
  46.   {
  47.     return exp(-0.5*s*s);
  48.   }
  49. };
  50.  
  51. int main()
  52. {
  53.   kernel G;
  54.  
  55.   Wrapper<kernel, MemberFunc<kernel, false, double(double)>::type<&kernel::gauss>> myKernel(&G);
  56.  
  57.   std::cout<< myKernel(0.0) <<std::endl;
  58.   std::cout<< myKernel(0.3) <<std::endl;
  59.  
  60.   return 0;
  61. }
Success #stdin #stdout 0s 3296KB
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stdin 
Standard input is empty
stdout 
1
0.955997
https://ideone.com/GuKTyR
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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