NAME¶

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

Synopsis¶

constexpr std::chrono::year_month& (1) (since C++20)
operator+=( const std::chrono::years& dy ) const noexcept;
constexpr std::chrono::year_month& (2) (since C++20)
operator+=( const std::chrono::months& dm ) const noexcept;
constexpr std::chrono::year_month& (3) (since C++20)
operator-=( const std::chrono::years& dy ) const noexcept;
constexpr std::chrono::year_month& (4) (since C++20)
operator-=( const std::chrono::months& dm ) const noexcept;

Modifies the time point *this represents by the duration dy or dm.

1) Equivalent to *this = *this + dy;.
2) Equivalent to *this = *this + dm;.
3) Equivalent to *this = *this - dy;.
4) Equivalent to *this = *this - dm;.

For durations that are convertible to both std::chrono::years and
std::chrono::months, the years overloads (1,3) are preferred if the call would
otherwise be ambiguous.

Example¶

// Run this code

#include <cassert>
#include <chrono>

int main()
{
auto ym{std::chrono::day(1)/7/2023};

ym -= std::chrono::years{2};
assert(ym.month() == std::chrono::July);
assert(ym.year() == std::chrono::year(2021));

ym += std::chrono::months{7};
assert(ym.month() == std::chrono::month(2));
assert(ym.year() == std::chrono::year(2022));
}

See also¶

operator+ performs arithmetic on year_month
operator- (function)
(C++20)