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91 lines
4.0 KiB
HTML
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<html><head><meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1">
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<title>Gregorian Date System Documentation</title>
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<link href="doxygen.css" rel="stylesheet" type="text/css">
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</head>
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<body>
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<a href="../../../index.htm">
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<img align="left" src="../../../c++boost.gif" alt="C++ Boost">
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</a>
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<p>
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<h1>Gregorian Date System Documentation</h1>
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<p> <p>
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<hr>
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<p>
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<p>
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<a href="index.html">Overall Index</a>
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<p>
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<a href="#intro">Introduction</a> --
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<a href="#usage">Usage Examples</a><p>
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<font class="bold">Temporal Types</font>
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<p>
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<a href="class_date.html">Class date</a> --
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<a href="class_date_duration.html">Class date_duration</a> --
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<a href="class_date_period.html">Class date_period</a>
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<p>
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<font class="bold">Other Topics</font>
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<p>
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<a href="date_iterators.html">Date Iterators</a> --
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<a href="date_algorithms.html">Date Generators / Algorithms</a> --
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<a href="class_gregorian_calendar.html">Class gregorian_calendar</a> --
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<a href="class_date.html#constructfromclock">Class day_clock</a>
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<p>
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<h2><a name="intro">Introduction</a></h2>
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<p>
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The gregorian date system provides a date programming system based the
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Gregorian Calendar. The first introduction of the Gregorian calendar was
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in 1582 to fix an error in the Julian Calendar. However, many local
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jurisdictions did not adopt this change until much later. Thus there
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is potential confusion with historical dates.
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<p>
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The implemented calendar is a "propleptic Gregorian calendar" which extends
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dates back prior to the Gregorian Calendar's first adoption in 1582.
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The current implementation supports dates in the range
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1400-Jan-01 to 10000-Jan-01. Many references will represent dates
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prior to 1582 using the Julian Calendar, so caution is in order if
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accurate calculations are required on historic
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dates.
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See <A href="http://emr.cs.iit.edu/home/reingold/calendar-book/second-edition/">Calendrical Calculations</A> by Reingold & Dershowitz for more details.
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Date information from Calendrical Calculations has been used to cross-test
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the correctness of the Gregorian calendar implementation.
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<p>
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All types for the gregorian system are found in namespace boost::gregorian.
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The library supports a convenience header <font class="el">boost/date_time/gregorian/gregorian_types.hpp</font> that will include all the classes of the
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library with no input/output dependency.
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Another header <font class="el">boost/date_time/gregorian/gregorian.hpp</font> will include the types and the input/output code.
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<p>
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The class <a href="class_date.html">boost::gregorian::date</a> is the primary
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temporal type for users. If you are interested in learning about writing
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programs do specialized date calculations such as finding the
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"first sunday in april" see the
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<a href="date_algorithms.html">date generators and algorithms page</a>.
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<p>
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<h2><a name="usage">Usage Examples</a></h2>
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<p>
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<table border=1 cellspacing=3 cellpadding=3><tr><td><b>Example</b></td><td><b>Description</b> </td></tr>
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<tr><td><a href="exp-days_alive.html">Days Alive</a> <a href="exp-days_till_new_year.html">Days Till New Year</a></td><td>Simple date arithmetic. Retrieve current day from clock. </td></tr>
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<tr><td><a href="exp-dates_as_strings.html">Dates as strings</a></td><td>Simple parsing and formatting of dates from/to strings </td></tr>
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<tr><td><a href="exp-period_calc.html">Date Period Calculations</a></td><td>See if a date is in a set of date periods (eg: is it a holiday/weekend) </td></tr>
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<tr><td><a href="exp-print_month.html">Print a month</a></td><td>Small utility program which prints out all the days in a month from command line. Need to know if 1999-Jan-1 was a Friday or a Saturday? This program shows how to do it. </td></tr>
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<tr><td><a href="exp-print_holidays.html">Print Holidays</a></td><td>Uses date generators to convert abstract specification into concrete set of dates. </td></table>
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<p>
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<hr>
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<address><small>
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<!-- hhmts start -->
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Last modified: Sun Feb 9 06:52:31 MST 2003
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<!-- hhmts end -->
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by Jeff Garland © 2000-2002
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</small></address>
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</body>
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</html>
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