std::basic_ios::widen
From cppreference.com
                    
                                        
                    
                    
                                                            
                    |   char_type widen( char c ) const;  | 
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Converts a character c to its equivalent in the current locale. The result is converted from char to character type used within the stream if needed.
Effectively calls std::use_facet< std::ctype<char_type> >(getloc()).widen(c).
[edit] Parameters
| c | - | character to convert | 
[edit] Return value
Character converted to char_type
[edit] See also
|    narrows characters  (public member function)  | |