std::chrono::weekday
From cppreference.com
                    
                                        
                    
                    
                                                            
                    | Defined in header  <chrono> | ||
| class weekday; | (since C++20) | |
| inline constexpr std::chrono::weekday Sunday{0}; | (since C++20) | |
| inline constexpr std::chrono::weekday Monday{1}; | (since C++20) | |
| inline constexpr std::chrono::weekday Tuesday{2}; | (since C++20) | |
| inline constexpr std::chrono::weekday Wednesday{3}; | (since C++20) | |
| inline constexpr std::chrono::weekday Thursday{4}; | (since C++20) | |
| inline constexpr std::chrono::weekday Friday{5}; | (since C++20) | |
| inline constexpr std::chrono::weekday Saturday{6}; | (since C++20) | |
The class weekday represent a day of the week in the Gregorian calendar. Its normal range is [0, 6], for Sunday through Saturday, but it can hold any value in the range [0, 255]. Seven named constants are predefined in the std::chrono namespace for the seven days of the week.
weekday is a TriviallyCopyable StandardLayoutType.
Member functions
| constructs a weekday(public member function) | |
| increments or decrements the weekday (public member function) | |
| adds or subtracts a number of days (public member function) | |
| retrieves the stored weekday value (public member function) | |
| checks if the stored weekday value is valid (public member function) | |
| convenience syntax for constructing a weekday_indexed or weekday_last from this weekday(public member function) | 
Nonmember functions
| compares two weekdayobjects(function) | |
| performs arithmetic on weekdays(function) | |
| outputs a weekdayinto a stream(function template) | |
| outputs a weekdayinto a stream according to the provided format(function template) | |
| parses a weekdayfrom a stream according to the provided format(function template) |