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

 

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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