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  1. #include <iostream>
  2. #include <vector>
  3. #include <list>
  4. #include <type_traits>
  5. #include <iterator>
  6.  
  7. // Figure out if contiguous here --> template function bool is_contiguous<Type>();
  8.  
  9. // User-defined iterator
  10. using Custom_Iterator = int*;
  11.  
  12. template<typename Iterator>
  13. constexpr auto is_contiguous()
  14. 	-> typename std::enable_if<std::is_same<Iterator,Custom_Iterator>::value, bool>::type
  15. {
  16. 	return true; // change to false if not actually contiguous
  17. }
  18.  
  19.  
  20. // Simple container
  21. template<typename Iterator>
  22. constexpr auto is_contiguous()
  23.     -> typename std::enable_if<std::is_same<Iterator,std::string::iterator>::value, bool>::type
  24. {
  25. 	return true;
  26. }
  27.  
  28.  
  29. // STL Containers (seems to require typename = void voodoo)
  30. template<typename Iterator, typename U = typename std::vector<typename std::iterator_traits<Iterator>::value_type>::iterator>
  31. constexpr auto is_contiguous()
  32.     -> typename std::enable_if<std::is_same<Iterator,U>::value, bool>::type
  33. {
  34. 	return true;
  35. }
  36.  
  37. template<typename Iterator, typename U = typename std::list<typename std::iterator_traits<Iterator>::value_type>::iterator, typename = void>
  38. constexpr auto is_contiguous()
  39.     -> typename std::enable_if<std::is_same<Iterator,U>::value, bool>::type
  40. {
  41. 	return false;
  42. }
  43.  
  44.  
  45.  
  46. // Do work here
  47. template<typename Iterator>
  48. auto f(Iterator beg, Iterator end)
  49.     -> typename std::enable_if< ! is_contiguous<Iterator>(), void>::type
  50. {
  51. 	std::cout << "Not contiguous:";
  52.     for(auto it = beg; it != end; it = std::next(it))
  53.     {
  54.         std::cout << " " << *it;
  55.     }
  56.     std::cout << std::endl;
  57. }
  58.  
  59. template<typename Iterator>
  60. auto f(Iterator beg, Iterator end)
  61.     -> typename std::enable_if<is_contiguous<Iterator>(), void>::type
  62. {
  63.     std::cout << "Contiguous:";
  64.     for(auto it = beg; it != end; it = std::next(it))
  65.     {
  66.         std::cout << " " << *it;
  67.     }
  68.     std::cout << std::endl;
  69. }
  70.  
  71.  
  72. int main()
  73. {
  74. 	std::cout << "Custom Data Set --> ";
  75.     int data[] = {1,2,3};
  76.     Custom_Iterator begin = data;
  77.     Custom_Iterator end = data+3;
  78.     f(begin, end);
  79.  
  80.     std::list<int> x = {1,2,3};
  81.     std::cout << "List --> ";
  82.     f(x.begin(), x.end());
  83.  
  84.     std::cout << "Vector<int> --> ";
  85.     std::vector<int> v = {1,2,3};
  86.     f(v.begin(), v.end());
  87.  
  88.     std::cout << "Vector<double> --> ";
  89.     std::vector<double> vd = {1.1,2.2,3.3};
  90.     f(vd.begin(), vd.end());
  91.  
  92.     std::cout << "String --> ";
  93.     std::string s = "WTF";
  94.     f(s.begin(), s.end());
  95. }
Success #stdin #stdout 0s 15240KB
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stdin
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Standard input is empty
stdout
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Custom Data Set --> Contiguous: 1 2 3
List --> Not contiguous: 1 2 3
Vector<int> --> Contiguous: 1 2 3
Vector<double> --> Contiguous: 1.1 2.2 3.3
String --> Contiguous: W T F
https://ideone.com/2zbG5Y
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
secret

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