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  1. #include <iostream>
  2. #include <typeinfo>
  3.  
  4. #include <type_traits>
  5. #include <bits/range_access.h>
  6.  
  7. /* comment the following line and everything is fine... */
  8. #define nsp
  9.  
  10. #ifdef nsp
  11. namespace test
  12. {
  13. #endif
  14.  
  15.  
  16. namespace detail
  17. {
  18. 	// To allow ADL with custom begin/end
  19. 	using std::begin;
  20. 	using std::end;
  21.  
  22. 	template <typename T>
  23. 	auto is_iterable_impl(int)
  24. 	-> decltype (
  25. 	    begin(std::declval<T&>()) != end(std::declval<T&>()), // begin/end and operator !=
  26. 	    ++std::declval<decltype(begin(std::declval<T&>()))&>(), // operator ++
  27. 	    *begin(std::declval<T&>()), // operator*
  28. 	    std::true_type {});
  29.  
  30. 	template <typename T>
  31. 	std::false_type is_iterable_impl(...);
  32.  
  33. }
  34.  
  35. template <typename T>
  36. using is_iterable = decltype(detail::is_iterable_impl<T>(0));
  37.  
  38.  
  39.  
  40.  
  41.  
  42. template <typename T,typename _F>
  43. inline typename std::enable_if< not is_iterable<T>::value >::type
  44. for_all_ele(T&& x,_F&& fn)
  45. {
  46. 	fn(x);
  47. }
  48.  
  49.  
  50. template <typename T,typename _F>
  51. inline typename std::enable_if< is_iterable<T>::value >::type
  52. for_all_ele(T&& arr,_F&& fn)
  53. {
  54. 	for(auto &x:arr)
  55. 		for_all_ele(x,fn);
  56.  
  57. }
  58.  
  59.  
  60. #ifdef nsp
  61. }
  62. using namespace test;
  63. #endif
  64.  
  65.  
  66.  
  67.  
  68. #include <iostream>
  69. using namespace std;
  70.  
  71. int main()
  72. {
  73. 	int x[2][5]= {1,2,5,68,9,12,35,6,32,89};
  74.  
  75. 	for_all_ele(x,[](int &xij){	cout<<xij<<",";	});
  76.  
  77. 	return 0;
  78. }
  79.  
  80.  
  81.  
  82.  
  83.  
  84.  
  85.  
  86.  
  87.  
  88.  
  89.  
Success #stdin #stdout 0s 3456KB
comments (?)
stdin 
Standard input is empty
stdout 
1,2,5,68,9,12,35,6,32,89,
https://ideone.com/17h75Q
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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