25 Iterators library [iterators]

25.6 Stream iterators [stream.iterators]

25.6.3 Class template ostream_iterator [ostream.iterator] General [ostream.iterator.general]

ostream_iterator writes (using operator<<) successive elements onto the output stream from which it was constructed.
If it was constructed with charT* as a constructor argument, this string, called a delimiter string, is written to the stream after every T is written.
namespace std { template<class T, class charT = char, class traits = char_traits<charT>> class ostream_iterator { public: using iterator_category = output_iterator_tag; using value_type = void; using difference_type = ptrdiff_t; using pointer = void; using reference = void; using char_type = charT; using traits_type = traits; using ostream_type = basic_ostream<charT,traits>; ostream_iterator(ostream_type& s); ostream_iterator(ostream_type& s, const charT* delimiter); ostream_iterator(const ostream_iterator& x); ~ostream_iterator(); ostream_iterator& operator=(const ostream_iterator&) = default; ostream_iterator& operator=(const T& value); ostream_iterator& operator*(); ostream_iterator& operator++(); ostream_iterator& operator++(int); private: basic_ostream<charT,traits>* out_stream; // exposition only const charT* delim; // exposition only }; }