std::chrono::operator ==,!=,<,<=,>,>= (std::chrono::year_month_day)
| constexpr bool operator==(const std::chrono::year_month_day& x,
                          const std::chrono::year_month_day& y) noexcept; | (1) | (since C++20) | 
| constexpr bool operator!=(const std::chrono::year_month_day& x,
                          const std::chrono::year_month_day& y) noexcept; | (2) | (since C++20) | 
| constexpr bool operator< (const std::chrono::year_month_day& x,
                          const std::chrono::year_month_day& y) noexcept; | (3) | (since C++20) | 
| constexpr bool operator> (const std::chrono::year_month_day& x,
                          const std::chrono::year_month_day& y) noexcept; | (4) | (since C++20) | 
| constexpr bool operator<=(const std::chrono::year_month_day& x,
                          const std::chrono::year_month_day& y) noexcept; | (5) | (since C++20) | 
| constexpr bool operator>=(const std::chrono::year_month_day& x,
                          const std::chrono::year_month_day& y) noexcept; | (6) | (since C++20) | 
Compares the two year_month_day objects x and y. This is a lexicographical comparison: the year() is compared first, then month(), then day().
Return value
1) 
 x.year() == y.year() && x.month() == y.month() && x.day() == y.day()
2) 
 !(x == y)
3) If 
 x.year() != y.year(), x.year() < y.year(); otherwise if x.month() != y.month(), x.month() < y.month(); otherwise x.day() < y.day()
4) 
 y < x
5) 
 !(y < x)
6) 
 !(x < y)
Notes
If both x and y represent valid dates (x.ok() && y.ok() == true), the result of the lexicographical comparison is consistent with the calendar order.
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