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119 lines
4.1 KiB
XML
119 lines
4.1 KiB
XML
<section id="date_time.gregorian.date_algorithms">
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<title>Date Generators/Algorithms</title>
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<link linkend="algo_intro">Introduction</link> --
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<link linkend="algo_header">Header</link> --
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<link linkend="algo_overview">Overview</link>
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<anchor id="algo_intro" />
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<bridgehead renderas="sect3">Introduction</bridgehead>
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<para>
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Date algorithms or generators are tools for generating other dates or schedules of dates. A generator function starts with some part of a date such as a month and day and is supplied another part to then generate a concrete date. This allows the programmer to represent concepts such as "The first Sunday in February" and then create a concrete set of dates when provided with one or more years.
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</para>
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<programlisting>
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using namespace boost::gregorian;
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typedef boost::date_time::nth_kday_of_month<date> nkday;
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nkday ldgen(nkday::first, Monday, Sep)); //US labor day
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date labor_day = ldgen.get_date(2002); //Calculate labor day for 2002
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</programlisting>
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<para>
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The <link linkend="date_time.examples.print_holidays">print holidays</link> example shows a detailed usage example.
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</para>
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<anchor id="algo_header" />
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<bridgehead renderas="sect3">Header</bridgehead>
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<para>
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#include "boost/date_time/date_generators.hpp"
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</para>
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<anchor id="algo_overview" />
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<bridgehead renderas="sect3">Overview</bridgehead>
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<informaltable frame="all">
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<tgroup cols="4">
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<thead>
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<row>
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<entry>Class</entry>
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<entry>Construction Parameters</entry>
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<entry>get_date Parameter</entry>
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<entry>Description</entry>
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<entry>Example</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>first_kday_after</entry>
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<entry> greg_day_of_week day_of_week</entry>
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<entry>date start_day</entry>
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<entry>Calculate something like First Sunday after Jan 1,2002</entry>
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<entry>
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first_kday_after fkaf(Monday);
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date d = fkaf.get_date(date(2002,Jan,1));//2002-Jan-07
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</entry>
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</row>
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<row>
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<entry>first_kday_before</entry>
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<entry> greg_day_of_week day_of_week</entry>
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<entry>date start_day</entry>
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<entry>Calculate something like First Monday before Feb 1,2002</entry>
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<entry>
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first_kday_before fkbf(Monday);
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date d = fkbf.get_date(date(2002,Feb,1));//2002-Jan-28
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</entry>
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</row>
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<row>
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<entry>year_based_generator</entry>
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<entry>abstract base class</entry>
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<entry>greg_year year</entry>
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<entry>A unifying date_generator base type for: partial_date, nth_day_of_the_week_in_month, first_day_of_the_week_in_month, and last_day_of_the_week_in_month
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</entry>
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<entry>
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<!--The <link linkend="date_time.examples.print_holidays">print holidays</link> example shows a detailed usage example. -->
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</entry>
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</row>
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<row>
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<entry>last_kday_of_month</entry>
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<entry>greg_day_of_week day_of_week greg_month month</entry>
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<entry>greg_year year</entry>
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<entry>Calculate something like last Monday of January</entry>
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<entry>
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last_kday_of_month lkm(Monday,Jan);
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date d = lkm.get_date(2002);//2002-Jan-28
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</entry>
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</row>
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<row>
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<entry>first_kday_of_month</entry>
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<entry>greg_day_of_week day_of_week greg_month month</entry>
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<entry>greg_year year</entry>
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<entry>Calculate something like first Monday of January</entry>
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<entry>
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first_kday_of_month fkm(Monday,Jan);
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date d = fkm.get_date(2002);//2002-Jan-07
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</entry>
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</row>
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<row>
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<entry>nth_day_of_the_week_in_month</entry>
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<entry>week_num day_of_week greg_month month</entry>
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<entry>greg_year year</entry>
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<entry>Calculate something like second Monday of January</entry>
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<entry>
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The <link linkend="date_time.examples.print_holidays">print holidays</link> example shows a detailed usage example.
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</entry>
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</row>
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<row>
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<entry>partial_date</entry>
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<entry>greg_day day_of_month greg_month month</entry>
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<entry>greg_year year</entry>
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<entry>Generates a date by applying the year to the given month and day.</entry>
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<entry>
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partial_date pd(1,Jan);
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date d = pd.get_date(2002);//2002-Jan-01
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</entry>
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</row>
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</tbody>
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</tgroup>
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</informaltable>
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<link linkend="top">top</link>
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</section>
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