cppreference.com > C++ Maps > insert insert Syntax:
      #include <map>
      iterator insert( iterator i, const TYPE& val );
      void insert( input_iterator start, input_iterator end );
      pair<iterator,bool> insert( const TYPE& val );
The function insert() either: inserts val after the element at pos (where pos is really just a suggestion as to where val should go, since sets and maps are ordered), and returns an iterator to that element. inserts a range of elements from start to end. inserts val, but only if val doesn't already exist. The return value is an iterator to the element inserted, and a boolean describing whether an insertion took place. Related topics: Map operators