std::chrono::year_month_day_last::operator+=, std::chrono::year_month_day_last::

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

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)

Example

Run this code
#include <cassert>
#include <chrono>
 
int main()
{
    auto ymdl{11/std::chrono::last/2020};
 
    ymdl += std::chrono::years(15);
    assert(ymdl.day() == std::chrono::day(30));
    assert(ymdl.month() == std::chrono::November);
    assert(ymdl.year() == std::chrono::year(2035));
 
    ymdl -= std::chrono::months(6);
    assert(ymdl.day() == std::chrono::day(31));
    assert(ymdl.month() == std::chrono::May);
    assert(ymdl.year() == std::chrono::year(2035));
}

See also

(C++20)
 adds or subtracts a year_month_day_last and some number of years or months
(function)
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