cppreference.com > C++ Strings > insert insert Syntax:
      #include <string>
      iterator insert( iterator i, const char& ch );
      string& insert( size_type index, const string& str );
      string& insert( size_type index, const char* str );
      string& insert( size_type index1, const string& str, size_type index2, size_type num );
      string& insert( size_type index, const char* str, size_type num );
      string& insert( size_type index, size_type num, char ch );
      void insert( iterator i, size_type num, const char& ch );
      void insert( iterator i, iterator start, iterator end );
The very multi-purpose insert() function either: inserts ch before the character denoted by i, inserts str into the current string, at location index, inserts a substring of str (starting at index2 and num characters long) into the current string, at location index1, inserts num characters of str into the current string, at location index, inserts num copies of ch into the current string, at location index, inserts num copies of ch into the current string, before the character denoted by i, or inserts the characters denoted by start and end into the current string, before the character specified by i. Related topics: erase replace