std::experimental::basic_string_view<CharT,Traits>::front
From cppreference.com
                    
                                        
                    < cpp | experimental | basic string view
                    
                                                            
                    |   constexpr const_reference front() const;  | 
(library fundamentals TS) | |
Returns reference to the first character in the view.
Parameters
(none)
Return value
reference to the first character, equivalent to operator[](0).
Complexity
Constant.
See also
|   accesses the last character  (public member function)  |