basic_string& insert( size_type index, size_type count, CharT ch ); (1) basic_string& insert( size_type index, const CharT* s ); (2) basic_string& insert( size_type index, const CharT* s, size_type count ); (3) basic_string& insert( size_type index, const basic_string& str ); (4) (5) basic_string& insert( size_type index, const basic_string& str,
size_type index_str, size_type count ); (until C++14) basic_string&a