std::front_insert_iterator

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C++ Standard Library
Iterator library
std::front_insert_iterator
Defined in header <iterator>

template< class Container >

class front_insert_iterator : public std::iterator< std::output_iterator_tag,

                                                   void,void,void,void >

std::front_insert_iterator is an output iterator that prepends elements to a container for which it was constructed, using the container's push_front() member function whenever the iterator (whether dereferenced or not) is assigned to. Incrementing the std::front_insert_iterator is a no-op.

Contents

[edit] Member types

Member type Definition
container_type Container

[edit] Member objects

Member name Definition
container (protected) a pointer of type Container*

[edit] Member functions

constructs a new front_insert_iterator
(public member function)
prepends an object to the associated container
(public member function)
no-op
(public member function of Template:cpp/iterator/front iterator/title)
no-op
(public member function of Template:cpp/iterator/front iterator/title)

Inherited from std::iterator

Member types

Member type Definition
value_type void
difference_type void
pointer void
reference void
iterator_category std::output_iterator_tag

[edit] 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_insert_iterator<std::deque<int>>(d)); // or std::front_inserter(d)
    for(int n : d)
        std::cout << n << ' ';
    std::cout << '\n';
}

Output: 

5 4 3 2 1

[edit] See also

creates a std::front_insert_iterator of type inferred from the argument
(function template)
iterator adaptor for insertion at the end of a container
(class template)
iterator adaptor for insertion into a container
(class template)
Retrieved from "http://en.cppreference.com/w/cpp/iterator/front_insert_iterator"