1<?xml version="1.0" encoding="utf-8"?> 2<!DOCTYPE library PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN" 3"../../../tools/boostbook/dtd/boostbook.dtd"> 4 5<!-- Copyright (c) 2001-2005 CrystalClear Software, Inc. 6 Subject to the Boost Software License, Version 1.0. 7 (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) 8--> 9 10<section id="date_time.gregorian.date_iterators"> 11 <title>Date Iterators</title> 12 13 <link linkend="iterators_intro">Introduction</link> -- 14 <link linkend="iterators_header">Header</link> -- 15 <link linkend="iterators_overview">Overview</link> 16 17 <anchor id="iterators_intro" /> 18 <bridgehead renderas="sect3">Introduction</bridgehead> 19 <para> 20 Date iterators provide a standard mechanism for iteration through dates. Date iterators are a model of <ulink url="http://www.sgi.com/tech/stl/BidirectionalIterator.html">Bidirectional Iterator</ulink> and can be used to populate collections with dates and other date generation tasks. For example, the <link linkend="date_time.examples.print_month">print month</link> example iterates through all the days in a month and prints them. 21 </para> 22 <para> 23 All of the iterators here derive from boost::gregorian::date_iterator. 24 </para> 25 26 <anchor id="iterators_header" /> 27 <bridgehead renderas="sect3">Header</bridgehead> 28 <para> 29 <programlisting>#include "boost/date_time/gregorian/gregorian.hpp" //include all types plus i/o 30or 31#include "boost/date_time/gregorian/gregorian_types.hpp" //no i/o just types</programlisting> 32 </para> 33 34 <anchor id="iterators_overview" /> 35 <bridgehead renderas="sect3">Overview</bridgehead> 36 <informaltable frame="all"> 37 <tgroup cols="2"> 38 <thead> 39 <row> 40 <entry valign="top" morerows="1">Syntax</entry> 41 <entry>Description</entry> 42 </row> 43 <row> 44 <entry>Example</entry> 45 </row> 46 </thead> 47 <tbody> 48 <row> 49 <entry valign="top" morerows="1"><screen>date_iterator</screen></entry> 50 <entry>Common (abstract) base class for all day level iterators.</entry> 51 </row> 52 <row> 53 <entry><screen></screen></entry> 54 </row> 55 56 <row> 57 <entry valign="top" morerows="1"><screen>day_iterator(date start_date, int day_count=1)</screen></entry> 58 <entry>Iterate <code>day_count</code> days at a time. This iterator does not provide postfix increment/decrement operators. Only prefix operators are provided.</entry> 59 </row> 60 <row> 61 <entry><screen>day_iterator day_itr(date(2005,Jan,1)); 62++d_itr; // 2005-Jan-02 63day_iterator 2day_itr(date(2005,Feb,1),2); 64++2d_itr; // 2005-Feb-03</screen></entry> 65 </row> 66 67 <row> 68 <entry valign="top" morerows="1"><screen>week_iterator(...) 69 Parameters: 70 date start_date 71 int week_offset (defaults to 1)</screen></entry> 72 <entry>Iterate <code>week_offset</code> weeks at a time. This iterator does not provide postfix increment/decrement operators. Only prefix operators are provided.</entry> 73 </row> 74 <row> 75 <entry><screen>week_iterator wk_itr(date(2005,Jan,1)); 76++wk_itr; // 2005-Jan-08 77week_iterator 2wk_itr(date(2005,Jan,1),2); 78++2wk_itr; // 2005-Feb-15</screen></entry> 79 </row> 80 81 <row> 82 <entry valign="top" morerows="1"><screen>month_iterator(...) 83 Parameters: 84 date start_date 85 int month_offset (defaults to 1)</screen></entry> 86<entry>Iterate <code>month_offset</code> months. There are special rules for handling the end of the month. These are: if start date is last day of the month, always adjust to last day of the month. If date is beyond the end of the month (e.g. Jan 31 + 1 month) adjust back to end of month (for more details and examples of this, see <link linkend="snap_to_details">Reversibility of Operations Pitfall</link>. <emphasis role="strong">NOTE:</emphasis> the <code>month_iterator</code> is not effected by this pitfall.) This iterator does not provide postfix increment/decrement operators. Only prefix operators are provided.</entry> 87 </row> 88 <row> 89 <entry><screen>month_iterator m_itr(date(2005,Jan,1)); 90++m_itr; // 2005-Feb-01 91month_iterator 2m_itr(date(2005,Feb,1),2); 92++2m_itr; // 2005-Apr-01</screen></entry> 93 </row> 94 95 <row> 96 <entry valign="top" morerows="1"><screen>year_iterator(...) 97 Parameters: 98 date start_date 99 int year_offset (defaults to 1)</screen></entry> 100 <entry>Iterate year_offset years. The year_iterator will always land on the day of the date parameter except when date is Feb 28 in a non-leap year. In this case the iterator will return Feb 29 for leap years (eg: 2003-Feb-28, 2004-Feb-29, 2005-Feb-28). This iterator does not provide postfix increment/decrement operators. Only prefix operators are provided.</entry> 101 </row> 102 <row> 103 <entry><screen>year_iterator y_itr(date(2005,Jan,1)); 104++y_itr; // 2006-Jan-01 105year_iterator 2y_itr(date(2005,Feb,1),2); 106++2y_itr; // 2007-Feb-01</screen></entry> 107 </row> 108 </tbody> 109 </tgroup> 110 </informaltable> 111 112 113</section> 114