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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 a LegacyOutputIterator that appends elements 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
iterator_category std::output_iterator_tag
value_type void
difference_type

void.

 (until C++20)

std::ptrdiff_t.

 (since C++20)
pointer void
reference void
container_type Container

Member types iterator_category, value_type, difference_type, pointer and reference are required to be obtained by inheriting from std::iterator<std::output_iterator_tag, void, void, void, void>.

 (until C++17)

Member functions

constructs a new back_insert_iterator
(public member function)
inserts an object into the associated container
(public member function)
no-op
(public member function)
no-op
(public member function)

Member objects

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

Example

#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), // C++17: std::back_insert_iterator(v)
    10, [n=0]() mutable { return ++n; }             // or use std::back_inserter helper
  );
 
  for (int n : v)
    std::cout << n << ' ';
  std::cout << '\n';
}

Output:

1 2 3 4 5 6 7 8 9 10

See also

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

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