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  1. #include <iterator>
  2.  
  3. template< typename Iter >
  4. struct Iterator
  5. {
  6. 	using underlying_iterator = Iter;
  7.  
  8. private:
  9.  
  10.     mutable underlying_iterator first,
  11.                           last;
  12.  
  13. public:
  14.  
  15. 	underlying_iterator begin() { return first; }
  16. 	underlying_iterator end() { return last; }
  17.  
  18.     operator bool() const
  19.     {
  20.         return first != last;
  21.     }
  22.  
  23.     Iterator& operator++()
  24.     {
  25.         ++first;
  26.         return *this;
  27.     }
  28.  
  29.     Iterator const& operator++() const
  30.     {
  31.         ++first;
  32.         return *this;
  33.     }
  34.  
  35.     Iterator operator++(int) const
  36.     {
  37.         Iterator other(*this);
  38.         ++first;
  39.         return other;
  40.     }
  41.  
  42.     explicit Iterator( underlying_iterator first,
  43. 					   underlying_iterator last ):
  44.     	first{first},
  45.     	last{last} {}
  46.  
  47. 	template< typename Container >
  48.     Iterator(Container& c) :
  49.     	Iterator{ std::begin(c), std::end(c) } {}
  50.  
  51.     decltype(*first) operator*()
  52.     {
  53.         return *first;
  54.     }
  55.  
  56.     decltype(*first) operator*() const
  57.     {
  58.         return *first;
  59.     }
  60. };
  61.  
  62. #include <vector>
  63. #include <iostream>
  64.  
  65. int main()
  66. {
  67.     std::vector<int> const v_const = {43, 38, 129};
  68.  
  69.     Iterator<std::vector<int>::const_iterator> it_const = v_const;
  70.  
  71.     while (it_const)
  72.         std::cout << *it_const++ << ' ';
  73. }
Success #stdin #stdout 0s 3428KB
comments (?)
stdin 
Standard input is empty
stdout 
43 38 129
https://ideone.com/j1JtWe
language:
C++14 (gcc 8.3)
created:
12 years ago
visibility:
public

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