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std::back_insert_iterator

From cppreference.com
< cpp‎ | iterator
 
 
Iterator library
Iterator concepts
Iterator primitives
Algorithm concepts and utilities
Indirect callable concepts
Common algorithm requirements
(C++20)
(C++20)
(C++20)
Utilities
(C++20)

Iterator adaptors
Iterator customization points
Iterator operations
(C++11)    
(C++11)
Range access
(C++11)(C++14)
(C++14)(C++14)    
(C++11)(C++14)
(C++14)(C++14)    
(C++17)(C++20)
(C++17)
(C++17)
 
 
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.

Contents

[edit] 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)

[edit] Member functions

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

[edit] Member objects

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

[edit] Example

#include <algorithm>
#include <iostream>
#include <iterator>
#include <vector>
 
int main()
{
    std::vector<int> v;
 
    std::generate_n(
        std::back_insert_iterator<std::vector<int>>(v),
            // Or use std::back_inserter helper
            // Or use std::back_insert_iterator(v) C++17's syntax
        10,
        [n = 0]() mutable { return ++n; }
    );
 
    for (int n : v)
        std::cout << n << ' ';
    std::cout << '\n';
}

Output:

1 2 3 4 5 6 7 8 9 10

[edit] See also

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