29 Time library [time]

29.8 The civil calendar [time.cal]

29.8.7 Class weekday_indexed [time.cal.wdidx]

29.8.7.1 Overview [time.cal.wdidx.overview]

namespace std::chrono { class weekday_indexed { chrono::weekday wd_; // exposition only unsigned char index_; // exposition only public: weekday_indexed() = default; constexpr weekday_indexed(const chrono::weekday& wd, unsigned index) noexcept; constexpr chrono::weekday weekday() const noexcept; constexpr unsigned index() const noexcept; constexpr bool ok() const noexcept; }; }

weekday_indexed represents a weekday and a small index in the range 1 to 5.

This class is used to represent the first, second, third, fourth, or fifth weekday of a month.

[Note 1:

A weekday_indexed object can be constructed by indexing a weekday with an unsigned.

— end note]

[Example 1: constexpr auto wdi = Sunday[2]; // wdi is the second Sunday of an as yet unspecified month static_assert(wdi.weekday() == Sunday); static_assert(wdi.index() == 2); — end example]

weekday_indexed is a trivially copyable and standard-layout class type.

29.8.7.2 Member functions [time.cal.wdidx.members]

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constexpr weekday_indexed(const chrono::weekday& wd, unsigned index) noexcept;

Effects: Initializes wd_ with wd and index_ with index.

The values held are unspecified if !wd.ok() or index is not in the range [0, 7].

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constexpr chrono::weekday weekday() const noexcept;

Returns: wd_.

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constexpr unsigned index() const noexcept;

Returns: index_.

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constexpr bool ok() const noexcept;

Returns: wd_.ok() && 1 <= index_ && index_ <= 5.

29.8.7.3 Non-member functions [time.cal.wdidx.nonmembers]

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constexpr bool operator==(const weekday_indexed& x, const weekday_indexed& y) noexcept;

Returns: x.weekday() == y.weekday() && x.index() == y.index().

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template<class charT, class traits>
  basic_ostream<charT, traits>&
    operator<<(basic_ostream<charT, traits>& os, const weekday_indexed& wdi);

Effects: Equivalent to: auto i = wdi.index(); return os << (i >= 1 && i <= 5 ? format(os.getloc(), STATICALLY-WIDEN<charT>("{:L}[{}]"), wdi.weekday(), i) : format(os.getloc(), STATICALLY-WIDEN<charT>("{:L}[{} is not a valid index]"), wdi.weekday(), i));