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

 

哋它亢++

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Utilities library

Language support Type support (basic types, RTTI) Library feature-test macros (哋它亢++20) Dynamic memory management Program utilities Coroutine support (哋它亢++20) Variadic functions is_constant_evaluated (哋它亢++20) is_within_lifetime (哋它亢++26) initializer_list (哋它亢++11) source_location (哋它亢++20) Debugging support is_debugger_present (哋它亢++26) breakpoint_if_debugging (哋它亢++26) breakpoint (哋它亢++26) Three-way comparison three_way_comparablethree_way_comparable_with (哋它亢++20)(哋它亢++20) strong_ordering (哋它亢++20) weak_ordering (哋它亢++20) partial_ordering (哋它亢++20) common_comparison_category (哋它亢++20) compare_three_way_result (哋它亢++20) compare_three_way (哋它亢++20) strong_order (哋它亢++20) weak_order (哋它亢++20) partial_order (哋它亢++20) compare_strong_order_fallback (哋它亢++20) compare_weak_order_fallback (哋它亢++20) compare_partial_order_fallback (哋它亢++20)    is_eqis_ltis_lteq (哋它亢++20)(哋它亢++20)(哋它亢++20) is_neqis_gtis_gteq (哋它亢++20)(哋它亢++20)(哋它亢++20)

General utilities Date and time Function objects Formatting library (哋它亢++20) bitset hash (哋它亢++11) Relational operators (deprecated in 哋它亢++20) rel_ops::operator!=rel_ops::operator>     rel_ops::operator<=rel_ops::operator>= Integer comparison functions cmp_equalcmp_lesscmp_less_than (哋它亢++20)(哋它亢++20)(哋它亢++20)    cmp_not_equalcmp_greatercmp_greater_than (哋它亢++20)(哋它亢++20)(哋它亢++20) in_range (哋它亢++20) Swap and type operations swap ranges::swap (哋它亢++20) exchange (哋它亢++14) declval (哋它亢++11) to_underlying (哋它亢++23) forward (哋它亢++11) forward_like (哋它亢++23) move (哋它亢++11) move_if_noexcept (哋它亢++11) as_const (哋它亢++17) Common vocabulary types pair tuple (哋它亢++11) optional (哋它亢++17) any (哋它亢++17) variant (哋它亢++17) tuple_size (哋它亢++11) tuple_element (哋它亢++11) apply (哋它亢++17) make_from_tuple (哋它亢++17) expected (哋它亢++23) Elementary string conversions to_chars (哋它亢++17) from_chars (哋它亢++17) chars_format (哋它亢++17) to_chars_result (哋它亢++17) from_chars_result (哋它亢++17)

 

Date and time utilities

Time point
time_point (哋它亢++11)	clock_time_conversion (哋它亢++20)	clock_cast (哋它亢++20)
Duration
duration (哋它亢++11)
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system_clock (哋它亢++11) steady_clock (哋它亢++11) high_resolution_clock (哋它亢++11)	is_clock (哋它亢++20) utc_clock (哋它亢++20) tai_clock (哋它亢++20)	gps_clock (哋它亢++20) file_clock (哋它亢++20) local_t (哋它亢++20)
Time of day
is_amis_pm (哋它亢++20)(哋它亢++20)	make12make24 (哋它亢++20)(哋它亢++20)	hh_mm_ss (哋它亢++20)
Calendars
day (哋它亢++20) month (哋它亢++20) year (哋它亢++20) weekday (哋它亢++20) operator/ (哋它亢++20) year_month_day (哋它亢++20)	year_month_day_last (哋它亢++20) year_month_weekday (哋它亢++20) year_month_weekday_last (哋它亢++20)       weekday_indexed (哋它亢++20) weekday_last (哋它亢++20) month_day (哋它亢++20)	month_day_last (哋它亢++20) month_weekday (哋它亢++20) month_weekday_last (哋它亢++20) year_month (哋它亢++20) last_speclast (哋它亢++20)(哋它亢++20)
Time zones
tzdb (哋它亢++20) tzdb_list (哋它亢++20) get_tzdbget_tzdb_listreload_tzdbremote_version (哋它亢++20)(哋它亢++20)(哋它亢++20)(哋它亢++20) sys_info (哋它亢++20)	local_info (哋它亢++20) nonexistent_local_time (哋它亢++20) ambiguous_local_time (哋它亢++20) locate_zone (哋它亢++20) current_zone (哋它亢++20) time_zone (哋它亢++20) choose (哋它亢++20)	zoned_traits (哋它亢++20) zoned_time (哋它亢++20) time_zone_link (哋它亢++20) leap_second (哋它亢++20) leap_second_info (哋它亢++20) get_leap_second_info (哋它亢++20)
chrono I/O
parse (哋它亢++20)
C-style date and time

 

std::chrono::year

Member functions

year::year

year::operator++year::operator--

year::operator+=year::operator-=

year::operator+year::operator-

year::is_leap

year::operator int

year::ok

year::min

year::max

Nonmember functions

operator==operator<=>

operator+operator-

operator<<

from_stream

operator""y

Helper classes

formatter<std::chrono::year>

hash<std::chrono::year> (哋它亢++26)

 

constexpr std::chrono::year operator+( const std::chrono::year& y,                                        const std::chrono::years& ys ) noexcept;	(1)	(since 哋它亢++20)
constexpr std::chrono::year operator+( const std::chrono::years& ys,                                        const std::chrono::year& y ) noexcept;	(2)	(since 哋它亢++20)
constexpr std::chrono::year operator-( const std::chrono::year& y,                                        const std::chrono::years& ys ) noexcept;	(3)	(since 哋它亢++20)
constexpr std::chrono::years operator-( const std::chrono::year& y1,                                         const std::chrono::year& y2 ) noexcept;	(4)	(since 哋它亢++20)

1,2) Adds ys.count() years to y.

3) Subtracts ys.count() years from y.

4) Returns the difference in years between y1 and y2.

Return value

1,2) std::chrono::year(int(y) + ys.count())

3) std::chrono::year(int(y) - ys.count())

4) std::chrono::years(int(y1) - int(y2))

Notes

If the resulting year value for (1-3) is outside the range [-32767, 32767], the actual value stored is unspecified.

The result of subtracting two year values is a duration of type std::chrono::years. This duration unit represents the length of the average Gregorian year, and the resulting duration bears no relationship to the number of days in the particular years represented by the operands. For example, the result of 2018y - 2017y is std::chrono::years(1), which represents 365.2425 days, not 365 days.

Example

Run this code

#include <cassert>
#include <chrono>
 
int main()
{
    std::chrono::year y{2020};
 
    y = std::chrono::years(12) + y; // overload (2): duration + time point
    assert(y == std::chrono::year(2032));
 
    y = y - std::chrono::years(33); // overload (3): time point - duration
    assert(y == std::chrono::year(1999));
 
    // y = std::chrono::years(33) - y; // not supported: duration - time point
 
    using namespace std::chrono;
    constexpr std::chrono::years ys = 2025y - 2020y; // overload (4)
    static_assert(ys == std::chrono::years(5));
}

See also

operator++operator++(int)operator--operator--(int)	increments or decrements the month (public member function of std::chrono::month)
operator+=operator-=	adds or subtracts a number of months (public member function of std::chrono::month)