std::front_insert_iterator (3) - Linux Manuals

std::front_insert_iterator: std::front_insert_iterator

NAME

std::front_insert_iterator - std::front_insert_iterator

Synopsis

Defined in header <iterator>
template< class Container >
class front_insert_iterator : public std::iterator< std::output_iterator_tag, (until C++17)
void,void,void,void >
template< class Container > (since C++17)
class front_insert_iterator;

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.

Member types

Member type Definition
container_type Container

Member functions

                constructs a new front_insert_iterator
constructor (public member function)
                inserts an object into the associated container
operator= (public member function)
                no-op
operator* (public member function)
                no-op
operator++ (public member function)
operator++(int)

Member objects

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

Member types

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

These member types are required to be obtained by inheriting from std::iterator<std::output_iterator_tag, void, void, void, void>. (until C++17)

Example

// Run this code

  #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