std::chrono::day::operator+=, std::chrono::day::operator-=

 

C++

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

 

Date and time utilities

Time point
time_point (C++11)	clock_time_conversion (C++20)	clock_cast (C++20)
Duration
duration (C++11)
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system_clock (C++11) steady_clock (C++11) high_resolution_clock (C++11)	is_clock (C++20) utc_clock (C++20) tai_clock (C++20)	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)
Calendars
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)
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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)
chrono I/O
parse (C++20)
C-style date and time

 

std::chrono::day

Member functions

day::day

day::operator++day::operator--

day::operator+=day::operator-=

day::operator unsigned

day::ok

Nonmember functions

operator==operator<=>

operator+operator-

operator<<

from_stream

operator""d

Helper classes

formatter<std::chrono::day>

 

constexpr std::chrono::day& operator+=( const std::chrono::days& d ) noexcept;	(1)	(since C++20)
constexpr std::chrono::day& operator-=( const std::chrono::days& d ) noexcept;	(2)	(since C++20)

Adds or subtracts d.count() days from the day value.

1) Equivalent to *this = *this + d;

2) Equivalent to *this = *this - d;

Return value

A reference to this day after modification

Notes

If the result would be outside the range [0, 255], the actual stored value is unspecified.

Example

Run this code

#include <cassert>
#include <chrono>
 
int main()
{
    std::chrono::day d {15};
 
    d += std::chrono::days(2);
    assert(d == std::chrono::day(17));
 
    d -= std::chrono::days{3};
    assert(d == std::chrono::day(14));
}

See also

operator++operator++(int)operator--operator--(int)	increments or decrements the day (public member function)
operator+operator- (C++20)	adds or subtracts a number of days and a day, or find the difference between two days (function)