std::inserter

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Iterator library

Iterator concepts

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

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input_iterator_tagoutput_iterator_tagforward_iterator_tagbidirectional_iterator_tagrandom_access_iterator_tagcontiguous_iterator_tag

(C++20)

iter_value_titer_difference_titer_reference_titer_const_reference_titer_rvalue_reference_titer_common_reference_t

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

iterator (deprecated in C++17)
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Algorithm concepts and utilities

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

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

(C++20)

(C++26)

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front_insert_iterator
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inserter
insert_iterator
front_inserter
back_inserter
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common_iterator (C++20)
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Range access

begincbegin (C++11)(C++14)
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endcend (C++11)(C++14)
rendcrend (C++14)(C++14)

sizessize (C++17)(C++20)
empty (C++17)
data (C++17)

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Defined in header`<iterator>`
template<class Container> std::insert_iterator<Container> inserter( Container& c,typename Container::iterator i);		(until C++20)
template<class Container> constexprstd::insert_iterator<Container> inserter( Container& c,ranges::iterator_t<Container> i);		(since C++20)

inserter is a convenience function template that constructs astd::insert_iterator for the containerc and its iteratori with the type deduced from the type of the argument.

[edit]Parameters

c	-	container that supports an`insert` operation
i	-	iterator inc indicating the insertion position

[edit]Return value

Astd::insert_iterator which can be used to insert elements into the containerc at the position indicated byi.

[edit]Possible implementation

template<class Container>std::insert_iterator<Container> inserter(Container& c,typename Container::iterator i){returnstd::insert_iterator<Container>(c, i);}

[edit]Example

Run this code

#include <algorithm>#include <iostream>#include <iterator>#include <set>#include <vector> int main(){std::multiset<int> s{1,2,3}; // std::inserter is commonly used with multi-setsstd::fill_n(std::inserter(s, s.end()),5,2); for(int n: s)std::cout<< n<<' ';std::cout<<'\n'; std::vector<int> d{100,200,300};std::vector<int> v{1,2,3,4,5}; // when inserting in a sequence container, insertion point advances// because each std::insert_iterator::operator= updates the target iteratorstd::copy(d.begin(), d.end(), std::inserter(v,std::next(v.begin()))); for(int n: v)std::cout<< n<<' ';std::cout<<'\n';}

Output:

1 2 2 2 2 2 2 3 1 100 200 300 2 3 4 5

[edit]Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 561	C++98	the type ofi was independent of`Container`	it is the iterator type of`Container`

[edit]See also

insert_iterator	iterator adaptor for insertion into a container (class template)[edit]
back_inserter	creates astd::back_insert_iterator of type inferred from the argument (function template)[edit]
front_inserter	creates astd::front_insert_iterator of type inferred from the argument (function template)[edit]