std::chrono::operator+, std::chrono::operator- (std::chrono::day)
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                    | constexpr std::chrono::day operator+(const std::chrono::day&  d, const std::chrono::days& ds) noexcept; | (1) | (since C++20) | 
| constexpr std::chrono::day operator+(const std::chrono::days& ds, const std::chrono::day& d) noexcept; | (2) | (since C++20) | 
| constexpr std::chrono::day operator-(const std::chrono::day&  d, const std::chrono::days& ds) noexcept; | (3) | (since C++20) | 
| constexpr std::chrono::days operator-(const std::chrono::day& x, const std::chrono::day& y) noexcept; | (4) | (since C++20) | 
1-2) Adds ds.count() days to 
d.3) Subtracts ds.count() days from 
d.4) Calculate the difference, in days, between two 
day x and y.Return value
1-2) std::chrono::day(unsigned(d) + ds.count())
3) std::chrono::day(unsigned(d) - ds.count())
4) std::chrono::days(int(unsigned(x)) - int(unsigned(y)))
Notes
For (1-3), if the result would be outside the range [0, 255], the actual stored value is unspecified.
Example
| This section is incomplete Reason: no example | 
See also
| increments or decrements the day (public member function) | |
| adds or subtracts a number of days (public member function) |