std::basic_string_view::front
From cppreference.com
                    
                                        
                    < cpp | string | basic string view
                    
                                                            
                    | constexpr const_reference front() const; | (since C++17) | |
Returns reference to the first character in the view. The behavior is undefined if empty() == true.
| Contents | 
[edit] Parameters
(none)
[edit] Return value
reference to the first character, equivalent to operator[](0).
[edit] Complexity
Constant.
[edit] See also
| accesses the last character (public member function) | |
| checks whether the view is empty (public member function) | 


