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    std::chrono::year_month_day::year_month_day

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    std::chrono::year_month_day
     
    year_month_day() = default;
    		(1) (since C++20) 
    constexpr year_month_day( const std::chrono::year& y,
                          const std::chrono::month& m,
                          const std::chrono::day& d ) noexcept;
    		(2) (since C++20) 
    constexpr year_month_day( const std::chrono::year_month_day_last& ymdl ) noexcept;
    		(3) (since C++20) 
    constexpr year_month_day( const std::chrono::sys_days& dp ) noexcept;
    		(4) (since C++20) 
    constexpr explicit year_month_day( const std::chrono::local_days& dp ) noexcept;
    		(5) (since C++20)

    Constructs a year_month_day object.

    1) Default constructor leaves the date uninitialized.
    2) Constructs a year_month_day object that stores the year y, month m and day d.
    3) Constructs a year_month_day object that stores the year ymdl.year(), month ymdl.month() and day ymdl.day().
    4) Constructs a year_month_day object that represent the same date as the one represented by dp.
    5) Constructs a year_month_day object that represent the same date as the one represented by dp, as if by year_month_day(sys_days(dp.time_since_epoch())).

    Constructors (3,4) define implicit conversions from std::chrono::year_month_day_last and std::chrono::sys_days, respectively.

    For any year_month_day object ymd representing a valid date (ymd.ok() == true), converting ymd to std::chrono::sys_days and back yields the same value.

    Notes

    A year_month_day can also be created by combining one of the partial-date types std::chrono::year_month and std::chrono::month_day with the missing component (day and year, respectively) using operator/.

    Example

    Run this code
    #include <chrono>
#include <iostream>

int main()
{
    using namespace std::chrono;

    constexpr auto ymd2 = std::chrono::year_month_day(
        2020y, std::chrono::January, 31d // overload (2)
    );
    std::cout << "ymd2: " << ymd2 << '\n';

    constexpr auto ymd3 = std::chrono::year_month_day(
        std::chrono::April / std::chrono::Monday[last] / 2023y // overload (3)
    );
    std::cout << "ymd3: " << ymd3 << '\n';

    const auto now = std::chrono::system_clock::now();
    const auto ymd4 = std::chrono::year_month_day(
        std::chrono::floor<std::chrono::days>(now) // overload (4)
    );
    std::cout << "ymd4: " << ymd4 << '\n';
}

    Possible output: 

    ymd2: 2020-01-31
ymd3: 2023-04-24
ymd4: 2023-08-30

    See also

    (C++20)
    		 conventional syntax for Gregorian calendar date creation
    (function)