# std::chrono::operator+, std::chrono::operator- (std::chrono::year_month_day_last)

From cppreference.com
< cpp‎ | chrono‎ | year month day last

Defined in header `<chrono>` |  |
constexpr std::chrono::year_month_day_last operator+( const std::chrono::year_month_day_last& ymdl, const std::chrono::months& dm ) noexcept; |  | (since C++20)
constexpr std::chrono::year_month_day_last operator+( const std::chrono::months& dm, const std::chrono::year_month_day_last& ymdl ) noexcept; |  | (since C++20)
constexpr std::chrono::year_month_day_last operator+( const std::chrono::year_month_day_last& ymdl, const std::chrono::years& dy ) noexcept; |  | (since C++20)
constexpr std::chrono::year_month_day_last operator+( const std::chrono::years& dy, const std::chrono::year_month_day_last& ymdl ) noexcept; |  | (since C++20)
constexpr std::chrono::year_month_day_last operator-( const std::chrono::year_month_day_last& ymdl, const std::chrono::months& dm ) noexcept; |  | (since C++20)
constexpr std::chrono::year_month_day_last operator-( const std::chrono::year_month_day_last& ymdl, const std::chrono::years& dy ) noexcept; |  | (since C++20)

1-2) Adds dm.count() months to the date represented by `ymdl`. The result has the same `year()` and `month()` as std::chrono::year_month(ymdl.year(), ymdl.month()) + dm.
3-4) Adds dy.count() years to the date represented by `ymdl`. The result is equivalent to std::chrono::year_month_day_last(ymdl.year() + dy, ymdl.month_day_last()).
5) Subtracts dm.count() months from the date represented by `ymdl`. Equivalent to ymdl + -dm.
6) Subtracts dy.count() years from the date represented by `ymdl`. Equivalent to ymdl + -dy.

For durations that are convertible to both std::chrono::years and std::chrono::months, the `years` overloads (3,4,6) are preferred if the call would otherwise be ambiguous.

### Example

Run this code

    #include <iostream>
    #include <chrono>

    int main()
    {
        std::cout << std::boolalpha;

        auto ymdl {11/std::chrono::last/2020};
        ymdl = std::chrono::years(10) + ymdl;
        std::cout << (ymdl == std::chrono::day(30)/
                              std::chrono::November/
                              std::chrono::year(2030)) << ' ';
        ymdl = ymdl - std::chrono::months(6);
        std::cout << (ymdl == std::chrono::day(31)/
                              std::chrono::May/
                              std::chrono::year(2030)) << '\n';
    }

Output:

    true true

Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/chrono/year_month_day_last/operator_arith_2&oldid=144065"