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  1. #include <iostream>
  2. #include <algorithm>
  3. #include <vector>
  4.  
  5. template<class It>
  6. class generating_iterator{
  7.   typedef generating_iterator this_type;
  8.  
  9. public:
  10.   typedef typename std::iterator_traits<It>::value_type value_type;
  11.  
  12.   generating_iterator(It first, It last)
  13.     : _first(first), _cur(_first), _last(last)
  14.   {
  15.   }
  16.  
  17.   value_type& operator()() const{
  18.     if(_cur == _last)
  19.       _cur = _first;
  20.     return *_cur++;
  21.   }
  22.  
  23. private:
  24.   It _first;
  25.   mutable It _cur;
  26.   It _last;
  27. };
  28.  
  29. template<class It>
  30. generating_iterator<It> make_gen_iter(It f, It l){
  31.   return {f, l};
  32. }
  33.  
  34. int main(){
  35.   std::vector<int> v1{1,2,3};
  36.   std::vector<int> v2(9);
  37.   std::generate(v2.begin(), v2.end(), make_gen_iter(v1.begin(), v1.end()));
  38.   for(int i=0; i < v2.size(); ++i)
  39.     std::cout << v2[i] << " ";
  40. }
Success #stdin #stdout 0s 2960KB
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Standard input is empty
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1 2 3 1 2 3 1 2 3
https://ideone.com/aLRMB
language:
C++14 (gcc 8.3)
created:
13 years ago
visibility:
public

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