std::front_inserter

< cpp‎ | iterator
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

#include <vector>
#include <deque>
#include <iostream>
#include <iterator>
#include <algorithm>
int main()
{
    std::vector<int> v{1,2,3,4,5};
    std::deque<int> d;
    std::copy(v.begin(), v.end(), std::front_inserter(d));
    for(int n : d)
        std::cout << n << ' ';
}

Output:

5 4 3 2 1

See also

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