Calendar and Time-Zones in C++20: Calendar Dates

// createCalendar.cpp

#include <iostream>
#include "date.h"
 
int main() {

    std::cout << std::endl;
    
    using namespace date;

    constexpr auto yearMonthDay{year(1940)/month(6)/day(26)};            // (1)
    std::cout << yearMonthDay << " ";
    std::cout << date::year_month_day(1940_y, June, 26_d) << std::endl;  // (2)

    std::cout << std::endl;

    constexpr auto yearMonthDayLast{year(2010)/March/last};              // (3)
    std::cout << yearMonthDayLast << " ";
    std::cout << date::year_month_day_last(2010_y, month_day_last(month(3))) <<  std::endl;

    constexpr auto yearMonthWeekday{year(2020)/March/Thursday[2]};       // (4)
    std::cout << yearMonthWeekday << " ";
    std::cout << date::year_month_weekday(2020_y, month(March), Thursday[2]) <<  std::endl;

    constexpr auto yearMonthWeekdayLast{year(2010)/March/Monday[last]};  // (5)
    std::cout << yearMonthWeekdayLast << " ";
    std::cout << date::year_month_weekday_last(2010_y, month(March), weekday_last(Monday)) <<  std::endl;

    std::cout << std::endl;

    constexpr auto day_{day(19)};          // (5)
    std::cout << day_  << " ";
    std::cout << date::day(19) << std::endl;

    constexpr auto month_{month(1)};       // (6)
    std::cout << month_  << " ";
    std::cout << date::month(1) << std::endl;

    constexpr auto year_{year(1988)};      // (7)
    std::cout << year_  << " ";
    std::cout << date::year(1988) << std::endl;

    constexpr auto weekday_{weekday(5)};
    std::cout << weekday_  << " ";
    std::cout << date::weekday(5) << std::endl;
 
    constexpr auto yearMonth{year(1988)/1};
    std::cout << yearMonth  << " ";
    std::cout << date::year_month(year(1988), January) << std::endl;
 
    constexpr auto monthDay{10/day(22)};
    std::cout << monthDay <<  " ";
    std::cout << date::month_day(October, day(22)) << std::endl;

    constexpr auto monthDayLast{June/last};
    std::cout << monthDayLast << " ";
    std::cout << date::month_day_last(month(6)) << std::endl;
 
    constexpr auto monthWeekday{2/Monday[3]};
    std::cout << monthWeekday << " ";
    std::cout << date::month_weekday(February, Monday[3]) << std::endl;
 
    constexpr auto monthWeekDayLast{June/Sunday[last]};
    std::cout << monthWeekDayLast << " ";
    std::cout << date::month_weekday_last(June, weekday_last(Sunday)) << std::endl;

    std::cout << std::endl;

}

// cuteSyntax.cpp

#include <iostream>
#include "date.h"

int main() {

    std::cout << std::endl;

    using namespace date;

    constexpr auto yearMonthDay{year(1966)/6/26};
    std::cout << yearMonthDay << std::endl;

    constexpr auto dayMonthYear{day(26)/6/1966};
    std::cout << dayMonthYear << std::endl;

    constexpr auto monthDayYear{month(6)/26/1966};
    std::cout << monthDayYear << std::endl;

    constexpr auto yearDayMonth{year(1966)/month(26)/6};  //(1)
    std::cout << yearDayMonth << std::endl;

    std::cout << std::endl;

}

// sysDays.cpp

#include <iostream>
#include "date.h"
 
int main() {

    std::cout << std::endl;
    
    using namespace date;

    constexpr auto yearMonthDayLast{year(2010)/March/last};
    std::cout << "sys_days(yearMonthDayLast): " << sys_days(yearMonthDayLast)  <<  std::endl;

    constexpr auto yearMonthWeekday{year(2020)/March/Thursday[2]};
    std::cout << "sys_days(yearMonthWeekday): " <<  sys_days(yearMonthWeekday) << std::endl;

    constexpr auto yearMonthWeekdayLast{year(2010)/March/Monday[last]};
    std::cout << "sys_days(yearMonthWeekdayLast): " << sys_days(yearMonthWeekdayLast) << std::endl;

    std::cout << std::endl;

    constexpr auto leapDate{year(2012)/February/last};                // (1)
    std::cout << "sys_days(leapDate): " << sys_days(leapDate) << std::endl;

    constexpr auto noLeapDate{year(2013)/February/last};              // (2)
    std::cout << "sys_day(noLeapDate): " << sys_days(noLeapDate) << std::endl;

    std::cout << std::endl;

}