std::chrono::operator/(日历)

 

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日期和时间库

时间点 time_point (C++11) clock_time_conversion (C++20)   clock_cast (C++20) 时长 duration (C++11) 时钟 system_clock (C++11) steady_clock (C++11) is_clock (C++20) utc_clock (C++20) tai_clock (C++20) high_resolution_clock (C++11) gps_clock (C++20) file_clock (C++20) local_t (C++20) 当天时刻 is_amis_pm (C++20)(C++20) make12make24 (C++20)(C++20) hh_mm_ss (C++20)

日历 day (C++20) month (C++20) year (C++20) weekday (C++20) operator/ (C++20) year_month_day (C++20) year_month_day_last (C++20) year_month_weekday (C++20) year_month_weekday_last (C++20)   weekday_indexed (C++20) weekday_last (C++20) month_day (C++20) month_day_last (C++20) month_weekday (C++20) month_weekday_last (C++20) year_month (C++20) last_speclast (C++20)(C++20) chrono I/O parse (C++20)

时区 tzdb (C++20) tzdb_list (C++20) get_tzdbget_tzdb_listreload_tzdbremote_version (C++20)(C++20)(C++20)(C++20) sys_info (C++20) local_info (C++20) nonexistent_local_time (C++20) ambiguous_local_time (C++20) locate_zone (C++20) current_zone (C++20) time_zone (C++20) choose (C++20) zoned_traits (C++20) zoned_time (C++20) time_zone_link (C++20) leap_second (C++20) leap_second_info (C++20) get_leap_second_info (C++20) C 风格日期和时间

 

在标头 <chrono> 定义
year_month
constexpr auto operator/( const std::chrono::year& y,                           const std::chrono::month& m ) noexcept     -> std::chrono::year_month;	(1)	(C++20 起)
constexpr auto operator/( const std::chrono::year& y, int m ) noexcept     -> std::chrono::year_month;	(2)	(C++20 起)
month_day
constexpr auto operator/( const std::chrono::month& m,                           const std::chrono::day& d ) noexcept     -> std::chrono::month_day;	(3)	(C++20 起)
constexpr auto operator/( const std::chrono::month& m, int d ) noexcept     -> std::chrono::month_day;	(4)	(C++20 起)
constexpr auto operator/( int m, const std::chrono::day& d ) noexcept     -> std::chrono::month_day;	(5)	(C++20 起)
constexpr auto operator/( const std::chrono::day& d,                           const std::chrono::month& m ) noexcept    -> std::chrono::month_day;	(6)	(C++20 起)
constexpr auto operator/( const std::chrono::day& d, int m ) noexcept     -> std::chrono::month_day;	(7)	(C++20 起)
month_day_last
constexpr auto operator/( const std::chrono::month& m,                          std::chrono::last_spec ) noexcept     -> std::chrono::month_day_last;	(8)	(C++20 起)
constexpr auto operator/( int m, std::chrono::last_spec ) noexcept     -> std::chrono::month_day_last;	(9)	(C++20 起)
constexpr auto operator/( std::chrono::last_spec,                           const std::chrono::month& m ) noexcept     -> std::chrono::month_day_last;	(10)	(C++20 起)
constexpr auto operator/( std::chrono::last_spec, int m ) noexcept     -> std::chrono::month_day_last;	(11)	(C++20 起)
month_weekday
constexpr auto operator/( const std::chrono::month& m,                           const std::chrono::weekday_indexed& wdi ) noexcept     -> std::chrono::month_weekday;	(12)	(C++20 起)
constexpr auto operator/( int m, const std::chrono::weekday_indexed& wdi ) noexcept     -> std::chrono::month_weekday;	(13)	(C++20 起)
constexpr auto operator/( const std::chrono::weekday_indexed& wdi,                           const std::chrono::month& m ) noexcept     -> std::chrono::month_weekday;	(14)	(C++20 起)
constexpr auto operator/( const std::chrono::weekday_indexed& wdi, int m ) noexcept     -> std::chrono::month_weekday;	(15)	(C++20 起)
month_weekday_last
constexpr auto operator/( const std::chrono::month& m,                           const std::chrono::weekday_last& wdl ) noexcept     -> std::chrono::month_weekday_last;	(16)	(C++20 起)
constexpr auto operator/( int m, const std::chrono::weekday_last& wdl ) noexcept     -> std::chrono::month_weekday_last;	(17)	(C++20 起)
constexpr auto operator/( const std::chrono::weekday_last& wdl,                           const std::chrono::month& m ) noexcept     -> std::chrono::month_weekday_last;	(18)	(C++20 起)
constexpr auto operator/( const std::chrono::weekday_last& wdl, int m ) noexcept     -> std::chrono::month_weekday_last;	(19)	(C++20 起)
year_month_day
constexpr auto operator/( const std::chrono::year_month& ym,                           const std::chrono::day& d ) noexcept     -> std::chrono::year_month_day;	(20)	(C++20 起)
constexpr auto operator/( const std::chrono::year_month& ym, int d ) noexcept     -> std::chrono::year_month_day;	(21)	(C++20 起)
constexpr auto operator/( const std::chrono::year& y,                           const std::chrono::month_day& md ) noexcept     -> std::chrono::year_month_day;	(22)	(C++20 起)
constexpr auto operator/( int y, const std::chrono::month_day& md ) noexcept     -> std::chrono::year_month_day;	(23)	(C++20 起)
constexpr auto operator/( const std::chrono::month_day& md,                           const std::chrono::year& y ) noexcept     -> std::chrono::year_month_day;	(24)	(C++20 起)
constexpr auto operator/( const std::chrono::month_day& md, int y ) noexcept     -> std::chrono::year_month_day;	(25)	(C++20 起)
year_month_day_last
constexpr auto operator/( const std::chrono::year_month& ym,                          std::chrono::last_spec ) noexcept     -> std::chrono::year_month_day_last;	(26)	(C++20 起)
constexpr auto operator/( const std::chrono::year& y,                           const std::chrono::month_day_last& mdl ) noexcept     -> std::chrono::year_month_day_last;	(27)	(C++20 起)
constexpr auto operator/( int y, const std::chrono::month_day_last& mdl ) noexcept     -> std::chrono::year_month_day_last;	(28)	(C++20 起)
constexpr auto operator/( const std::chrono::month_day_last& mdl,                           const std::chrono::year& y ) noexcept     -> std::chrono::year_month_day_last;	(29)	(C++20 起)
constexpr auto operator/( const std::chrono::month_day_last& mdl, int y ) noexcept     -> std::chrono::year_month_day_last;	(30)	(C++20 起)
year_month_weekday
constexpr auto operator/( const std::chrono::year_month& ym,                           const std::chrono::weekday_indexed& wdi ) noexcept     -> std::chrono::year_month_weekday;	(31)	(C++20 起)
constexpr auto operator/( const std::chrono::year& y,                           const std::chrono::month_weekday& mwd ) noexcept     -> std::chrono::year_month_weekday;	(32)	(C++20 起)
constexpr auto operator/( int y, const std::chrono::month_weekday& mwd ) noexcept     -> std::chrono::year_month_weekday;	(33)	(C++20 起)
constexpr auto operator/( const std::chrono::month_weekday& mwd,                           const std::chrono::year& y ) noexcept     -> std::chrono::year_month_weekday;	(34)	(C++20 起)
constexpr auto operator/( const std::chrono::month_weekday& mwd, int y ) noexcept     -> std::chrono::year_month_weekday;	(35)	(C++20 起)
year_month_weekday_last
constexpr auto operator/( const std::chrono::year_month& ym,                           const std::chrono::weekday_last& wdl ) noexcept     -> std::chrono::year_month_weekday_last;	(36)	(C++20 起)
constexpr auto operator/( const std::chrono::year& y,                           const std::chrono::month_weekday_last& mwdl ) noexcept     -> std::chrono::year_month_weekday_last;	(37)	(C++20 起)
constexpr auto operator/( int y, const std::chrono::month_weekday_last& mwdl ) noexcept     -> std::chrono::year_month_weekday_last;	(38)	(C++20 起)
constexpr auto operator/( const std::chrono::month_weekday_last& mwdl,                           const std::chrono::year& y ) noexcept     -> std::chrono::year_month_weekday_last;	(39)	(C++20 起)
constexpr auto operator/( const std::chrono::month_weekday_last& mwdl, int y ) noexcept     -> std::chrono::year_month_weekday_last;	(40)	(C++20 起)

这些 operator/ 为创建外推格里高利历日期提供约定语法。

对于创建完整日期，任何下列三种顺序都可接受：

• year/month/day，
• month/day/year，
• day/month/year。

每种情况中，能以下列之一替换 day：

• std::chrono::last，用于月的最后一日；
• weekday[i]，用于月的第 i 个 weekday；
• weekday[std::chrono::last]，用于该月的最后一个 weekday。

若单纯的整数的含义相对于其他运算数的类型无歧义，则可接受它：允许 2005y/4/5，但不允许 5/April/2005。

可以不应用三种顺序之一的第二个 operator/，以创建部分日期类型（year_month、month_day 等）。

返回值

1)std::chrono::year_month(y, m)

2)std::chrono::year_month(y, std::chrono::month(m))

3,6)std::chrono::month_day(m, d)

4)std::chrono::month_day(m, std::chrono::day(d))

5,7)std::chrono::month_day(std::chrono::month(m), d)

8,10)std::chrono::month_day_last(m)

9,11)std::chrono::month_day_last(std::chrono::month(m))

12,14)std::chrono::month_weekday(m, wdi)

13,15)std::chrono::month_weekday(std::chrono::month(m), wdi)

16,18)std::chrono::month_weekday_last(m, wdl)

17,19)std::chrono::month_weekday_last(std::chrono::month(m), wdl)

20)std::chrono::year_month_day(ym.year(), ym.month(), d)

21)std::chrono::year_month_day(ym.year(), ym.month(), std::chrono::day(d))

22,24)std::chrono::year_month_day(y, md.month(), md.day())

23,25)std::chrono::year_month_day(std::chrono::year(y), md.month(), md.day())

26)std::chrono::year_month_day_last(ym.year(), std::chrono::month_day_last(ym.month()))

27,29)std::chrono::year_month_day_last(y, mdl)

28,30)std::chrono::year_month_day_last(std::chrono::year(y), mdl)

31)std::chrono::year_month_weekday(ym.year(), ym.month(), wdi)

32,34)std::chrono::year_month_weekday(y, mwd.month(), mwd.weekday_indexed())

33,35)std::chrono::year_month_weekday(std::chrono::year(y), mwd.month(), mwd.weekday_indexed())

36)std::chrono::year_month_weekday_last(ym.year(), ym.month(), wdl)

37,39)std::chrono::year_month_weekday_last(y, mwdl.month(), mwdl.weekday_last())

38,40)std::chrono::year_month_weekday_last(std::chrono::year(y), mwdl.month(), mwdl.weekday_last())

示例

运行此代码

#include <chrono>
using namespace std::chrono;
 
constexpr auto ym{2021y/8};
static_assert(ym == year_month(year(2021), August));
 
constexpr auto md{9/15d};
static_assert(md == month_day(September, day(15)));
 
constexpr auto mdl{October/last};
static_assert(mdl == month_day_last(month(10)));
 
constexpr auto mw{11/Monday[3]};
static_assert(mw == month_weekday(November, Monday[3]));
 
constexpr auto mwdl{December/Sunday[last]};
static_assert(mwdl == month_weekday_last(month(12), weekday_last(Sunday)));
 
// 这个世界内外人们实际使用的三种年/月/日顺序：
constexpr auto ymd{year(2021)/January/day(23)};
static_assert(ymd == month{1}/23/2021);
static_assert(ymd == day{23}/1/2021);
static_assert(ymd == year_month_day(2021y, month(January), 23d));
 
int main() {}