std::chrono::operator+, std::chrono::operator- (std::chrono::year_month_day)

 

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Date and time library

Time point time_point (C++11) clock_time_conversion (C++20)   clock_cast (C++20) Duration duration (C++11) Clocks 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) Time of day is_amis_pm (C++20)(C++20) make12make24 (C++20)(C++20) hh_mm_ss (C++20)

Calendar 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)

Time zone 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-style date and time

 

std::chrono::year_month_day

Member functions

year_month_day::year_month_day

year_month_day::operator+=year_month_day::operator-=

year_month_day::yearyear_month_day::monthyear_month_day::day

year_month_day::operator sys_daysyear_month_day::operator local_days

year_month_day::ok

Nonmember functions

operator==operator<=>

operator+operator-

operator<<

from_stream

Helper classes

formatter<std::chrono::year_month_day>

hash<std::chrono::year_month_day> (C++26)

 

Defined in header <chrono>
constexpr std::chrono::year_month_day operator+( const std::chrono::year_month_day& ymd,                                                  const std::chrono::months& dm                                                ) noexcept;		(since C++20)
constexpr std::chrono::year_month_day operator+( const std::chrono::months& dm,                                                  const std::chrono::year_month_day& ymd                                                ) noexcept;		(since C++20)
constexpr std::chrono::year_month_day operator+( const std::chrono::year_month_day& ymd,                                                  const std::chrono::years& dy                                                ) noexcept;		(since C++20)
constexpr std::chrono::year_month_day operator+( const std::chrono::years& dy,                                                  const std::chrono::year_month_day& ymd                                                ) noexcept;		(since C++20)
constexpr std::chrono::year_month_day operator-( const std::chrono::year_month_day& ymd,                                                  const std::chrono::months& dm                                                ) noexcept;		(since C++20)
constexpr std::chrono::year_month_day operator-( const std::chrono::year_month_day& ymd,                                                  const std::chrono::years& dy                                                ) noexcept;		(since C++20)

1,2) Adds dm.count() months to the date represented by ymd. The result has the same day() as ymd and the same year() and month() as std::chrono::year_month(ymd.year(), ymd.month() + dm.

3,4) Adds dy.count() years to the date represented by ymd. The result is equivalent to std::chrono::year_month_day(ymd.year() + dy, ymd.month(), ymd.day().

5) Subtracts dm.count() months from the date represented by ymd. Equivalent to ymd + -dm.

6) Subtracts dy.count() years from the date represented by ymd. Equivalent to ymd + -dy.

For durations that are convertible to both std::chrono::years and std::chrono::months, the years overloads (3,4,6) are preferred if the call would otherwise be ambiguous.

Notes

Even if ymd.ok() is true, the resulting year_month_day may not represent a valid date if ymd.day() is 29, 30, or 31.

Example

Run this code

#include <chrono>
#include <iostream>
 
int main()
{
    std::cout << std::boolalpha;
 
    auto ymd{std::chrono::day(1)/std::chrono::July/2021};
 
    ymd = ymd + std::chrono::months(4);
    std::cout << (ymd.month() == std::chrono::November) << ' '
              << (ymd.year() == std::chrono::year(2021) << ' ';
 
    ymd = ymd - std::chrono::years(10);
    std::cout << (ymd.month() == std::chrono::month(11) << ' '
              << (ymd.year() == std::chrono::year(2011) << '\n';
}

Output:

true true true true

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