std:: front_insert_iterator

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indirectly_readable (C++20)
indirectly_writable (C++20)
weakly_incrementable (C++20)
incrementable (C++20)
is-integer-like is-signed-integer-like (C++20) (C++20)

sentinel_for (C++20)
sized_sentinel_for (C++20)
input_iterator (C++20)
output_iterator (C++20)
input_or_output_iterator (C++20)

forward_iterator (C++20)
bidirectional_iterator (C++20)
random_access_iterator (C++20)
contiguous_iterator (C++20)

Iterator primitives

input_iterator_tag output_iterator_tag forward_iterator_tag bidirectional_iterator_tag random_access_iterator_tag contiguous_iterator_tag

(C++20)

iter_value_t iter_difference_t iter_reference_t iter_const_reference_t iter_rvalue_reference_t iter_common_reference_t

(C++20) (C++20) (C++20) (C++23) (C++20) (C++20)

iterator (deprecated in C++17)
iterator_traits
incrementable_traits (C++20)
indirectly_readable_traits (C++20)

Algorithm concepts and utilities

Indirect callable concepts

indirectly_unary_invocable indirectly_regular_unary_invocable

(C++20) (C++20)

indirect_unary_predicate (C++20)
indirect_binary_predicate (C++20)

indirect_equivalence_relation (C++20)
indirect_strict_weak_order (C++20)

Common algorithm requirements

indirectly_movable (C++20)
indirectly_movable_storable (C++20)
indirectly_copyable (C++20)

indirectly_copyable_storable (C++20)
indirectly_swappable (C++20)
indirectly_comparable (C++20)

permutable (C++20)
mergeable (C++20)
sortable (C++20)

Utilities

indirect_result_t

(C++20)

projected

(C++20)

projected_value_t

(C++26)

Iterator adaptors

reverse_iterator
make_reverse_iterator (C++14)
move_iterator (C++11)
make_move_iterator (C++11)
default_sentinel_t default_sentinel (C++20) (C++20)
unreachable_sentinel_t unreachable_sentinel (C++20) (C++20)

front_insert_iterator
back_insert_iterator
inserter
insert_iterator
front_inserter
back_inserter
move_sentinel (C++20)

common_iterator (C++20)
counted_iterator (C++20)
basic_const_iterator (C++23)
const_iterator (C++23)
const_sentinel (C++23)
make_const_iterator (C++23)
make_const_sentinel (C++23)

Stream iterators

istream_iterator
ostream_iterator

istreambuf_iterator
ostreambuf_iterator

Iterator customization points
ranges::iter_move (C++20)
ranges::iter_swap (C++20)

Iterator operations

advance
distance
prev (C++11)
next (C++11)

ranges::advance (C++20)
ranges::distance (C++20)
ranges::prev (C++20)
ranges::next (C++20)

Range access

begin cbegin (C++11) (C++14)
rbegin crbegin (C++14) (C++14)

end cend (C++11) (C++14)
rend crend (C++14) (C++14)

size ssize (C++17) (C++20)
empty (C++17)
data (C++17)

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

std::front_insert_iterator is a LegacyOutputIterator that prepends elements to a container for which it was constructed. The container's push_front() member function is called whenever the iterator (whether dereferenced or not) is assigned to. Incrementing the std::front_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

(constructor)	constructs a new `front_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 *

Example

Run this code

#include <algorithm>
#include <deque>
#include <iostream>
#include <iterator>
#include <vector>
 
namespace stb
{
    void println(auto, auto const& d)
    {
        std::ranges::copy(d, std::ostream_iterator<int>(std::cout, " "));
        std::cout << '\n';
    }
}
 
int main()
{
    std::vector<int> v{1, 2, 3, 4, 5};
    std::deque<int> d;
 
    std::copy(v.begin(), v.end(),
              std::front_insert_iterator<std::deque<int>>(d));
              // or std::front_inserter(d)
 
    stb::println("{}", d);
}

Output:

5 4 3 2 1

Compiler support
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Language
Standard library
Standard library headers
Named requirements
Feature test macros (C++20)
Language support library
Concepts library (C++20)
Metaprogramming library (C++11)
Diagnostics library
General utilities library
Strings library
Containers library
Iterators library
Ranges library (C++20)
Algorithms library
Numerics library
Localizations library
Input/output library
Filesystem library (C++17)
Regular expressions library (C++11)
Concurrency support library (C++11)
Execution support library (C++26)
Technical specifications
Symbols index
External libraries

Member functions
front_insert_iterator::front_insert_iterator
front_insert_iterator::operator=
front_insert_iterator::operator*
front_insert_iterator::operator++ front_insert_iterator::operator++(int)

std:: front_insert_iterator

Member types

Member functions

Member objects

Example

See also

Navigation

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