C++

Reference

<iterator>

ostream_iterator

class template
<iterator>

std::ostream_iterator

template <class T, class charT=char, class traits=char_traits<charT> > class ostream_iterator;
Ostream iterator

Ostream iterators are output iterators that write sequentially to an output stream (such as cout).

They are constructed from a basic_ostream object, to which they become associated, so that whenever an assignment operator (=) is used on the ostream_iterator (dereferenced or not) it inserts a new element into the stream.

Optionally, a delimiter can be specified on construction. This delimiter is written to the stream after each element is inserted.

Template parameters

T
Element type for the iterator: The type of elements inserted into the stream
charT
First template parameter of the associated basic_ostream object: The type of elements the stream handles (char for ostream).
traits
Second template parameter of the associated basic_ostream: Character traits for the elements the stream handles.
Note: The default template arguments correspond to an instantiation that uses an ostream object as associated stream.

Member types

memberdefinition in istream_iteratordescription
ostream_typebasic_ostream<charT,traits>Type of the associated output stream
iterator_categoryoutput_iterator_tagInput iterator
value_typevoid
char_typecharTType of the characters handled by the associated stream
traits_typetraitsCharacter traits for associated stream
difference_typevoid
pointervoid
referencevoid

Member functions

(constructor)
Construct ostream iterator (public member function)
operator*
Dereference iterator (public member function)
operator++
Increment iterator (public member function)
operator=
Assignment operator (public member function)

Example

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// ostream_iterator example #include <iostream> // std::cout #include <iterator> // std::ostream_iterator #include <vector> // std::vector #include <algorithm> // std::copy int main () { std::vector<int> myvector; for (int i=1; i<10; ++i) myvector.push_back(i*10); std::ostream_iterator<int> out_it (std::cout,", "); std::copy ( myvector.begin(), myvector.end(), out_it ); return 0; }

Possible output:
 10, 20, 30, 40, 50, 60, 70, 80, 90,


Possible implementation

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template <class T, class charT=char, class traits=char_traits<charT> > class ostream_iterator : public iterator<output_iterator_tag, void, void, void, void> { basic_ostream<charT,traits>* out_stream; const charT* delim; public: typedef charT char_type; typedef traits traits_type; typedef basic_ostream<charT,traits> ostream_type; ostream_iterator(ostream_type& s) : out_stream(&s), delim(0) {} ostream_iterator(ostream_type& s, const charT* delimiter) : out_stream(&s), delim(delimiter) { } ostream_iterator(const ostream_iterator<T,charT,traits>& x) : out_stream(x.out_stream), delim(x.delim) {} ~ostream_iterator() {} ostream_iterator<T,charT,traits>& operator= (const T& value) { *out_stream << value; if (delim!=0) *out_stream << delim; return *this; } ostream_iterator<T,charT,traits>& operator*() { return *this; } ostream_iterator<T,charT,traits>& operator++() { return *this; } ostream_iterator<T,charT,traits>& operator++(int) { return *this; } };

See also

istream_iterator
Istream iterator (class template)
output_iterator_tag
Output iterator category (class)
ostream
Output Stream (class)