std::chrono::weekday_last
From cppreference.com
                    
                                        
                    
                    
                                                            
                    |   Defined in header  <chrono>
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|   class weekday_last;  | 
(since C++20) | |
The class weekday_last represents the last weekday of some month.
weekday_last is a TriviallyCopyable StandardLayoutType.
Member functions
  constructs a weekday_last object (public member function)  | |
|    accesses the stored weekday   (public member function)  | |
|    checks if the stored weekday is valid   (public member function)  | 
Nonmember functions
   compares two weekday_last objects  (function)  | |
   outputs a weekday_last into a stream  (function template)  |