std::front_inserter

 

C++

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Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

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Iterators library

Ranges library (C++20)

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Numerics library

Input/output library

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Regular expressions 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
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advance
distance
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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::front_insert_iterator<Container> front_inserter( Container& c );		(until C++20)
template< class Container > constexpr std::front_insert_iterator<Container> front_inserter( Container& c );		(since C++20)

front_inserter is a convenience function template that constructs a std::front_insert_iterator for the container c with the type deduced from the type of the argument.

Parameters

c

-

container that supports a push_front operation

Return value

A std::front_insert_iterator which can be used to add elements to the beginning of the container c

Possible implementation

template< class Container > std::front_insert_iterator<Container> front_inserter( Container& c ) { return std::front_insert_iterator<Container>(c); }

Example

Run this code

#include <iostream>
#include <deque>
#include <algorithm>
#include <iterator>
 
int main()
{
    std::deque<int> v{1,2,3,4,5,6,7,8,9,10};
    std::fill_n(std::front_inserter(v), 3, -1);
    for (int n : v)
        std::cout << n << ' ';
}

Output:

-1 -1 -1 1 2 3 4 5 6 7 8 9 10

See also

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