std::back_insert_iterator

C++

Language

Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

Iterator library

Iterator primitives
iterator_traits
input_iterator_tagoutput_iterator_tagforward_iterator_tagbidirectional_iterator_tagrandom_access_iterator_tag
iterator
Iterator adaptors
reverse_iterator move_iterator (C++11) back_insert_iterator front_insert_iterator insert_iterator	make_reverse_iterator (C++14) make_move_iterator (C++11) back_inserter front_inserter inserter
Stream iterators
istream_iterator
ostream_iterator
istreambuf_iterator
ostreambuf_iterator
Iterator operations
advance
distance
prev (C++11)
next (C++11)
Range access
begincbegin (C++11)(C++14)
endcend (C++11)(C++14)
rbegincrbegin (C++14)(C++14)
rendcrend (C++14)(C++14)
Container access
size (C++17)
empty (C++17)
data (C++17)

std::back_insert_iterator

Member functions

back_insert_iterator::back_insert_iterator

back_insert_iterator::operator=

back_insert_iterator::operator*

back_insert_iterator::operator++back_insert_iterator::operator++(int)

Defined in header <iterator>
template< class Container > class back_insert_iterator : public std::iterator< std::output_iterator_tag, void, void, void, void >		(until C++17)
template< class Container > class back_insert_iterator;		(since C++17)

std::back_insert_iterator is an OutputIterator that appends to a container for which it was constructed. The container's push_back() member function is called whenever the iterator (whether dereferenced or not) is assigned to. Incrementing the std::back_insert_iterator is a no-op.

Member types

Member type	Definition
container_type	Container

Member functions

(constructor)	constructs a new back_insert_iterator (public member function)
operator=	inserts an object into the associated container (public member function)
operator*	no-op (public member function)
operator++operator++(int)	no-op (public member function)

Member objects

Member name	Definition
container (protected)	a pointer of type Container*

Member types

Member type	Definition
value_type	void
difference_type	void
pointer	void
reference	void
iterator_category	std::output_iterator_tag

These member types are required to be obtained by inheriting from std::iterator<std::output_iterator_tag,void,void,void,void>.

(until C++17)

Example

Run this code

#include <iostream>
#include <iterator>
#include <algorithm>
#include <vector>

int main()
{
    std::vector<int> v;
    std::generate_n(std::back_insert_iterator<std::vector<int>>(v), // can be simplified
                    10, [n=0]() mutable { return ++n; });        // with std::back_inserter
    for (int n : v)
        std::cout << n << ' ';
    std::cout << '\n';
}

Output:

1 2 3 4 5 6 7 8 9 10

See also

back_inserter	creates a std::back_insert_iterator of type inferred from the argument (function template)
front_insert_iterator	iterator adaptor for insertion at the front of a container (class template)
insert_iterator	iterator adaptor for insertion into a container (class template)