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last_spec struct

  • Artikkeli

Indicates the last item in a month. For example, the last day of the week of a month, such as the last Tuesday of February 2020. Or the last day of a month, such as the last day of April 2019.

Syntax

struct last_spec; // C++20
inline constexpr last_spec last{} // C++20

Example: last

Use last_spec to indicate the last item in a month. The following example uses last to indicate the:

  • Last day in December as a monthDayLast
  • Last Friday in July of 2021 as a year_month_weekday_last
  • Last day in April of 1975 as a year_month_day_last
// compile using: /std:c++latest
#include <iostream>
#include <chrono>

using namespace std::chrono;

int main()
{
    constexpr auto monthDayLast{December/last}; // 'last' resolves to last_spec
    std::cout << monthDayLast << '\n';

    constexpr auto yearMonthWeekDayLast{year(2021)/July/Friday[last]}; // 'last' resolves to last_spec
    std::cout << yearMonthWeekDayLast << '\n';

    constexpr auto yearMonthDayLast{ April / last / 1975 };
    std::cout << yearMonthDayLast << "\n";  

    return 0;
}

Dec/last
2021/Jul/Fri[last]
1975/Apr/last

Members

Name Description
Constructor Construct a last_spec.

Requirements

Header: <chrono> (since C++20)

Namespace: std::chrono

Compiler Option: /std:c++latest

Constructor

Construct a last_spec.

explicit last_spec() = default;

Remarks

You typically won't create a last_spec instance directly. You'll use last as shown above in Example last.

See also

<chrono>
month_day_last Class
month_weekday_last class
Header Files Reference