< cpp‎ | iterator
Iterator library
Iterator concepts
Iterator primitives
Iterator adaptors
Stream iterators
Iterator customization points
Iterator operations
Range access
Defined in header <iterator>
template< class Container >

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

                                                   void,void,void,void >
(until C++17)
template< class Container >
class front_insert_iterator;
(since C++17)

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


[edit] Member types

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

Member types iterator_category, value_type, difference_type, pointer and reference are required to be obtained by inheriting from std::iterator<std::output_iterator_tag, void, void, void, void>.

(until C++17)

[edit] Member functions

constructs a new front_insert_iterator
(public member function) [edit]
inserts an object into the associated container
(public member function) [edit]
(public member function) [edit]
(public member function) [edit]

[edit] Member objects

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

[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';


5 4 3 2 1

[edit] See also

creates a std::front_insert_iterator of type inferred from the argument
(function template) [edit]
iterator adaptor for insertion at the end of a container
(class template) [edit]
iterator adaptor for insertion into a container
(class template) [edit]