NAME

std::chrono::year_month_day_last::operatorsys_days, - std::chrono::year_month_day_last::operatorsys_days,

Synopsis

constexpr operator std::chrono::sys_days() const noexcept; (1) (since C++20)
explicit constexpr operator std::chrono::local_days() const (2) (since C++20)
noexcept;

Converts *this to a std::chrono::time_point representing the same date as this
year_month_day_last. This is equivalent to composing a year_month_day from year(),
month() and day() and converting that year_month_day to the destination type.

1) Equivalent to std::chrono::sys_days(year()/month()/day())
2) Equivalent to std::chrono::local_days(year()/month()/day())

Example

// Run this code

#include <array>
#include <chrono>
#include <iostream>
#include <string_view>
using namespace std::chrono;
using namespace std::literals;

int main()
{
constexpr std::array weekdays {
"Sunday"sv, "Monday"sv, "Tuesday"sv, "Wednesday"sv,
"Thursday"sv, "Friday"sv, "Saturday"sv
};
constexpr std::array quarters {
"1st"sv, "2nd"sv, "3rd"sv, "4th"sv
};
constexpr auto mq {12 / 4}; // months per quarter
constexpr year y {2021y};
std::cout << "In " << static_cast<int>(y) << " the\n";
for (auto q = 1; q < 5; ++q) {
const auto ls = y / month(q * mq) / Sunday[last];
const auto ld = y / month(q * mq) / last;
// subtract last Sunday from last day for day of week
const auto index = (sys_days(ld) - sys_days(ls)).count();
std::cout << quarters[q - 1] << " quarter ends on a "
<< weekdays[index] << (q < 4 ? ',':'.') << '\n';
}
}

Output:

In 2021 the
1st quarter ends on a Wednesday,
2nd quarter ends on a Wednesday,
3rd quarter ends on a Thursday,
4th quarter ends on a Friday.

See also

operator sys_days converts to a std::chrono::time_point
operator local_days (public member function of std::chrono::year_month_day)