std::back_insert_iterator

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`

Note: before C++17, these member types are required to be obtained by inheriting from std::iterator<std::output_iterator_tag,void,void,void,void>.

Example

#include <iostream>
#include <iterator>
#include <algorithm>
#include <cstdlib>
#include <vector>
  
int main()
{
    std::vector<int> v;
    std::generate_n(std::back_insert_iterator<std::vector<int>>(v), // can be simplified
                    10, [](){ return std::rand() % 10; });        // with std::back_inserter
    for (int n : v)
        std::cout << n << ' ';
    std::cout << '\n';
}

Output:

1	`3 6 7 5 3 5 6 2 9 1`

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)

std::back_insert_iterator

Member types

Member functions

Member objects

Member types

Example

See also