fork(4) download
copy 
  1. #include <iostream>
  2. #include <type_traits>
  3. #include <typeinfo>
  4.  
  5. template<typename ...Args>
  6. struct holder;
  7.  
  8. namespace
  9. {
  10. 	template<typename ...Args>
  11. 	struct print_helper;
  12.  
  13. 	template<typename Arg, typename ...Args>
  14. 	struct print_helper<Arg, Args...>
  15. 	{
  16. 		static void print()
  17. 		{
  18. 			std::cout << typeid(Arg).name() << ", ";
  19. 			print_helper<Args...>::print();
  20. 		}
  21. 	};
  22.  
  23. 	template<typename Arg>
  24. 	struct print_helper<Arg>
  25. 	{
  26. 		static void print()
  27. 		{
  28. 			std::cout << typeid(Arg).name() << std::endl;
  29. 		}
  30. 	};
  31.  
  32. 	template<typename ...Args>
  33. 	struct print_helper<holder<Args...>>
  34. 	{
  35. 		static void print()
  36. 		{
  37. 			print_helper<Args...>::print();
  38. 		}
  39. 	};
  40. }
  41.  
  42. template<typename ...Args>
  43. void print()
  44. {
  45. 	print_helper<Args...>::print();
  46. }
  47.  
  48. namespace
  49. {
  50. 	template<typename Applier, typename T>
  51. 	struct apply_helper
  52. 	{
  53. 		typedef typename Applier::template apply<T>::type type;
  54. 	};
  55.  
  56. 	template<typename Applier, typename ... Args>
  57. 	struct transform_helper
  58. 	{
  59. 		typedef holder<typename apply_helper<Applier, Args>::type...> type;
  60. 	};
  61. }
  62.  
  63. template<typename Applier, typename ... Args>
  64. struct transform
  65. {
  66. 	typedef typename transform_helper<Applier, Args...>::type type;
  67. };
  68.  
  69. template<typename Applier, typename ... Args>
  70. struct transform<Applier, holder<Args...>>
  71. {
  72. 	typedef typename transform<Applier, Args...>::type type;
  73. };
  74.  
  75. namespace
  76. {
  77. 	template<typename T>
  78. 	struct type_replacer_helper
  79. 	{
  80. 		typedef T type;
  81. 	};
  82.  
  83. 	template<>
  84. 	struct type_replacer_helper<int>
  85. 	{
  86. 		typedef float type;
  87. 	};
  88. }
  89.  
  90. struct type_replacer
  91. {
  92. 	template<typename T>
  93. 	struct apply
  94. 	{
  95. 		typedef typename type_replacer_helper<T>::type type;
  96. 	};
  97. };
  98.  
  99. using namespace std;
  100.  
  101. int main() {
  102.  
  103. 	typedef holder<int, int, char, int, float> t1;
  104. 	typedef typename transform<type_replacer, t1>::type t2;
  105.  
  106. 	print<t1>();
  107. 	print<t2>();
  108.  
  109. 	return 0;
  110. }
Success #stdin #stdout 0s 3296KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
i, i, c, i, f
f, f, c, f, f
https://ideone.com/tb6Jm7
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!