Insert Iterators

An insert iterator implements its assignment operator to call the container's push_back(), push_front(), or insert() member function.

There are three kinds of insert iterators:
               1) Front Inserter (front_inserter())
               2) Back Inserter (back_inserter())
               3) General Inserter (inserter())
They can be used on containers that have the corresponding member functions (push_front(), push_back(), and insert()).

Reference: The C++ Standard Library: A Tutorial and Reference by Nicolai M. Josuttis. Addison-Wesley, 1999, p. 272.