std::chrono::year_month_weekday::operator+=,std::chrono::year_month_weekday::operator-=(3)

NAME
std::chrono::year_month_weekday::operator+=,std::chrono::year_month_weekday::operator-= - std::chrono::year_month_weekday::operator+=,std::chrono::year_month_weekday::operator-=

Synopsis
   constexpr std::chrono::year_month_weekday& (1) (since C++20)
       operator+=( const std::chrono::years& dy ) const noexcept;
   constexpr std::chrono::year_month_weekday& (2) (since C++20)
       operator+=( const std::chrono::months& dm ) const noexcept;
   constexpr std::chrono::year_month_weekday& (3) (since C++20)
       operator-=( const std::chrono::years& dy ) const noexcept;
   constexpr std::chrono::year_month_weekday& (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>
 #include <iostream>
 int main()
 {
     auto ymwi{1/std::chrono::Wednesday[2]/2021};
     std::cout << ymwi << '\n';
     ymwi += std::chrono::years(5);
     std::cout << ymwi << '\n';
     assert(static_cast<std::chrono::year_month_day>(ymwi) ==
                        std::chrono::year(2026)/1/14);
     ymwi -= std::chrono::months(1);
     std::cout << ymwi << '\n';
     assert(static_cast<std::chrono::year_month_day>(ymwi) ==
                        std::chrono::day(10)/12/2025);
 }

Output:
 2021/Jan/Wed[2]
 2026/Jan/Wed[2]
 2025/Dec/Wed[2]

See also
   operator+ adds or subtracts a year_month_weekday and some number of years or months
   operator- (function)
   (C++20)