ปฏิทินและเขตเวลา

#include <iostream>
#include <chrono>

int main() {
    using namespace std::chrono;
    year y{2026};
    std::cout << "Year value: " << static_cast<int>(y) << '\n';
    return 0;
}

#include <iostream>
#include <chrono>

int main() {
    using namespace std::chrono;
    auto y = 2026y;
    auto d = 15d;
    std::cout << static_cast<int>(y) << " / " << static_cast<unsigned>(d) << '\n';
    return 0;
}

#include <iostream>
#include <chrono>

int main() {
    using namespace std::chrono;
    year_month_day ymd = 2026y/May/30;
    std::cout << static_cast<int>(ymd.year()) << "-"
              << static_cast<unsigned>(ymd.month()) << "-"
              << static_cast<unsigned>(ymd.day()) << '\n';
    return 0;
}

#include <iostream>
#include <chrono>

int main() {
    using namespace std::chrono;
    year_month_day good = 2026y/February/28;
    year_month_day bad = 2026y/February/30;
    std::cout << std::boolalpha << good.ok() << " " << bad.ok() << '\n';
    return 0;
}

#include <iostream>
#include <chrono>

int main() {
    using namespace std::chrono;
    sys_days a = sys_days{2026y/May/30};
    sys_days b = sys_days{2026y/May/20};
    std::cout << "Days apart: " << (a - b).count() << '\n';
    return 0;
}

#include <iostream>
#include <chrono>

int main() {
    using namespace std::chrono;
    sys_days start = sys_days{2026y/May/30};
    sys_days later = start + days{10};
    year_month_day ymd = later;
    std::cout << static_cast<unsigned>(ymd.day()) << "/"
              << static_cast<unsigned>(ymd.month()) << '\n';
    return 0;
}

#include <iostream>
#include <chrono>

int main() {
    using namespace std::chrono;
    weekday wd{sys_days{2026y/May/30}};
    std::cout << "Weekday index (Sun=0): " << wd.c_encoding() << '\n';
    return 0;
}

#include <iostream>
#include <chrono>

int main() {
    using namespace std::chrono;
    year_month_day_last eom = 2024y/February/last;
    year_month_day ymd = eom;
    std::cout << "Feb 2024 ends on day " << static_cast<unsigned>(ymd.day()) << '\n';
    return 0;
}

#include <iostream>
#include <chrono>

int main() {
    using namespace std::chrono;
    std::cout << std::boolalpha;
    std::cout << "2024 leap: " << year{2024}.is_leap() << '\n';
    std::cout << "2026 leap: " << year{2026}.is_leap() << '\n';
    return 0;
}

#include <iostream>
#include <chrono>

int main() {
    using namespace std::chrono;
    auto today = floor<days>(system_clock::now());
    year_month_day ymd = sys_days{today};
    std::cout << "Year is in range: " << (static_cast<int>(ymd.year()) > 2000) << '\n';
    return 0;
}

#include <iostream>
#include <chrono>

int main() {
    using namespace std::chrono;
    auto now = system_clock::now();
    auto days_part = floor<days>(now);
    std::cout << "Have a UTC time point: " << (days_part.time_since_epoch().count() > 0) << '\n';
    return 0;
}