27 Time library [time]

27.8 The civil calendar [time.cal]

27.8.16 Class year_­month_­weekday [time.cal.ymwd]

27.8.16.3 Non-member functions [time.cal.ymwd.nonmembers]

constexpr bool operator==(const year_month_weekday& x, const year_month_weekday& y) noexcept;
Returns:
x.year() == y.year() && x.month() == y.month() && x.weekday_indexed() == y.weekday_indexed()
constexpr year_month_weekday operator+(const year_month_weekday& ymwd, const months& dm) noexcept;
Returns: (ymwd.year() / ymwd.month() + dm) / ymwd.weekday_­indexed().
constexpr year_month_weekday operator+(const months& dm, const year_month_weekday& ymwd) noexcept;
Returns: ymwd + dm.
constexpr year_month_weekday operator-(const year_month_weekday& ymwd, const months& dm) noexcept;
Returns: ymwd + (-dm).
constexpr year_month_weekday operator+(const year_month_weekday& ymwd, const years& dy) noexcept;
Returns: {ymwd.year()+dy, ymwd.month(), ymwd.weekday_­indexed()}.
constexpr year_month_weekday operator+(const years& dy, const year_month_weekday& ymwd) noexcept;
Returns: ymwd + dm.
constexpr year_month_weekday operator-(const year_month_weekday& ymwd, const years& dy) noexcept;
Returns: ymwd + (-dm).
template<class charT, class traits> basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>& os, const year_month_weekday& ymwd);
Returns: os << ymwdi.year() << '/' << ymwdi.month() << '/' << ymwdi.weekday_­indexed().