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std::insert_iterator

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

std::insert_iterator is a LegacyOutputIterator that inserts elements into a container for which it was constructed, at the position pointed to by the supplied iterator. The container's insert() member function is called whenever the iterator (whether dereferenced or not) is assigned to. Incrementing the std::insert_iterator is a no-op.

Member types

Member type Definition
iterator_category std::output_iterator_tag
value_type void
difference_type

void.

 (until C++20)

std::ptrdiff_t.

 (since C++20)
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)

Member functions

constructs a new insert_iterator
(public member function)
inserts an object into the associated container
(public member function)
no-op
(public member function)
no-op
(public member function)

Member objects

Member name Definition
container (protected member object) a pointer of type Container*
iter (protected member object) an iterator of type Container::iterator (until C++20) ranges::iterator_t<Container> (since C++20)

Example

#include <vector>
#include <list>
#include <iostream>
#include <iterator>
#include <algorithm>
 
int main()
{
    std::vector<int> v{1,2,3,4,5};
    std::list<int> l{-1,-2,-3};
    std::copy(v.begin(), v.end(), // may be simplified with std::inserter
              std::insert_iterator<std::list<int>>(l, std::next(l.begin()))); 
    for (int n : l)
        std::cout << n << ' ';
    std::cout << '\n';
}

Output:

-1 1 2 3 4 5 -2 -3

See also

creates a std::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 at the front of a container
(class template)

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