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std::chrono::operator/ (calendar)

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

These operator/ overloads provide a conventional syntax for the creation of Gregorian calendar dates.

For creation of a full date, any of the following three orders are accepted:

  • year/month/day
  • month/day/year
  • day/month/year.

In each case day can replaced with one of:

  • std::chrono::last, for the last day of the month;
  • weekday[i], for the i-th weekday of the month;
  • weekday[std::chrono::last], for the last weekday of the month.

A plain integer is accepted if its meaning is unambiguous from the types of other operands: 2005y/4/5 is allowed, but 5/April/2005 is not.

Partial-date types (year_month, month_day, etc.) can be created by not applying the second operator/ in any of the three orders.

Return value

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())

Example 

#include <iostream>
#include <chrono>
using namespace std::chrono;
 
int main()
{
    std::cout << std::boolalpha;
 
    constexpr auto ym {2021y/8};
    std::cout << (ym == year_month(year(2021), August)) << ' ';
 
    constexpr auto md {9/15d};
    std::cout << (md == month_day(September, day(15))) << ' ';
 
    constexpr auto mdl {October/last};
    std::cout << (mdl == month_day_last(month(10))) << ' ';
 
    constexpr auto mw {11/Monday[3]};
    std::cout << (mw == month_weekday(November, Monday[3])) << ' ';
 
    constexpr auto mwdl {December/Sunday[last]};
    std::cout << (mwdl == month_weekday_last(month(12), weekday_last(Sunday))) << ' ';
 
    // Those three year/month/day orders that people actually use on this planet:
    constexpr auto ymd {year(2021)/January/day(23)};
    static_assert(ymd == month{1}/23/2021);
    static_assert(ymd == day{23}/1/2021);
    std::cout << (ymd == year_month_day(2021y, month(January), 23d)) << '\n';
}

Output:

true true true true true true

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