std::inserter

 

C++

Language

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Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

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Regular expressions library (C++11)

Atomic operations library (C++11)

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Technical Specifications

 

Iterator library

Iterator primitives
iterator_traits
input_iterator_tagoutput_iterator_tagforward_iterator_tagbidirectional_iterator_tagrandom_access_iterator_tag
iterator
Iterator adaptors
reverse_iterator move_iterator (C++11) back_insert_iterator front_insert_iterator insert_iterator	make_reverse_iterator (C++14) make_move_iterator (C++11) back_inserter front_inserter inserter
Stream iterators
istream_iterator
ostream_iterator
istreambuf_iterator
ostreambuf_iterator
Iterator operations
advance
distance
prev (C++11)
next (C++11)
Range access
begincbegin (C++11)(C++14)
endcend (C++11)(C++14)
rbegincrbegin (C++14)(C++14)
rendcrend (C++14)(C++14)
Container access
size (C++17)
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 > constexpr std::insert_iterator<Container> inserter( Container& c, typename Container::iterator 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 a 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 ) { return std::insert_iterator<Container>(c, i); }

Example

Run this code

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

Output:

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

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)