std::insert_iterator<Container>::insert_iterator

From cppreference.com

insert_iterator() = default;
(1) (since C++20)
(2)
insert_iterator( Container& c, typename Container::iterator i );
(until C++20)
constexpr  insert_iterator( Container& c, ranges::iterator_t<Container> i );
(since C++20)
1) Initializes the underlying pointer to container with nullptr and value-initializes the underlying iterator.
(since C++20)
2) Initializes the underlying pointer to the container to std::addressof(c) and the underlying iterator to i.

Parameters

c - container to initialize the inserter with
i - iterator to initialize the inserter with