std::match_results::empty
From cppreference.com
                    
                                        
                    < cpp | regex | match results
                    
                                                            
                    | bool empty() const; | (since C++11) | |
Checks whether the match was successful.
| Contents | 
[edit] Parameters
(none)
[edit] Return value
true if the match_results object contains no matches., false otherwise
[edit] Exceptions
(none)
[edit] Complexity
Constant.
[edit] See also
| returns the number of matches in a fully-established result state (public member function) | 


