std::inserter

 

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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 begincbegin (C++11)(C++14) rbegincrbegin (C++14)(C++14)   endcend (C++11)(C++14) rendcrend (C++14)(C++14)   sizessize (C++17)(C++20) empty (C++17) data (C++17)

 

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 a std::insert_iterator for the container c and its iterator i with the type deduced from the type of the argument.

Parameters

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

Return value

A std::insert_iterator which can be used to insert elements into the container c at the position indicated by i.

Possible implementation

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

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

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 of i was independent of Container	it is the iterator type of Container

See also

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