std::chrono::operator+,std::chrono::operator-(std::chrono::year_month_weekday)(3) | C++ Standard Libary | std::chrono::operator+,std::chrono::operator-(std::chrono::year_month_weekday)(3) |
NAME¶
std::chrono::operator+,std::chrono::operator-(std::chrono::year_month_weekday) - std::chrono::operator+,std::chrono::operator-(std::chrono::year_month_weekday)
Synopsis¶
constexpr std::chrono::year_month_weekday
operator+(const std::chrono::year_month_weekday& ymwd, const (1)
(since C++20)
std::chrono::months& dm) noexcept;
constexpr std::chrono::year_month_weekday
operator+(const std::chrono::months& dm, const (2) (since
C++20)
std::chrono::year_month_weekday& ymwd) noexcept;
constexpr std::chrono::year_month_weekday
operator+(const std::chrono::year_month_weekday& ymwd, const (3)
(since C++20)
std::chrono::years& dy) noexcept;
constexpr std::chrono::year_month_weekday
operator+(const std::chrono::years& dy, const (4) (since
C++20)
std::chrono::year_month_weekday& ymwd) noexcept;
constexpr std::chrono::year_month_weekday
operator-(const std::chrono::year_month_weekday& ymwd, const (5)
(since C++20)
std::chrono::months& dm) noexcept;
constexpr std::chrono::year_month_weekday
operator-(const std::chrono::year_month_weekday& ymwd, const (6)
(since C++20)
std::chrono::years& dy) noexcept;
1-2) Adds dm.count() months to the date represented by ymwd. The result has
the same
year() and month() as std::chrono::year_month(ymwd.year(), ymwd.month()) + dm
and
the same weekday() and index() as ymwd.
3-4) Adds dy.count() years to the date represented by ymwd. The result is
equivalent
to std::chrono::year_month_weekday(ymwd.year() + dy, ymwd.month(),
ymwd.weekday_indexed()).
5) Subtracts dm.count() months from the date represented by ymwd. Equivalent
to ymwd
+ -dm.
6) Subtracts dy.count() years from the date represented by ymwd. Equivalent
to ymwd
+ -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 ymwd.ok() is true, the resulting year_month_weekday may
not represent a
valid date if ymwd.index() is 5.
Example¶
// Run this code
#include <iostream>
#include <chrono>
int main()
{
std::cout << std::boolalpha;
auto ymwdi {1/std::chrono::Wednesday[1]/2021};
ymwdi = std::chrono::years(5) + ymwdi;
// First Wednesday in January, 2026
std::cout << (static_cast<std::chrono::year_month_day>(ymwdi) ==
std::chrono::January/7/2026) << ' ';
ymwdi = ymwdi - std::chrono::months(6);
// First Wednesday in July, 2025
std::cout << (static_cast<std::chrono::year_month_day>(ymwdi) ==
std::chrono::July/2/2025) << '\n';
}
Output:¶
true true
2022.07.31 | http://cppreference.com |