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- <?xml version="1.0" encoding="utf-8"?>
- <!DOCTYPE library PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN"
- "../../../tools/boostbook/dtd/boostbook.dtd">
- <!-- Copyright (c) 2001-2005 CrystalClear Software, Inc.
- Subject to the Boost Software License, Version 1.0.
- (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
- -->
- <section id="date_time.examples.general_usage_examples">
- <title>General Usage Examples</title>
- <para>
- The following provides some sample usage of dates.
- See <link linkend="date_time.gregorian">Date Programming</link>
- for more details.
- <programlisting><emphasis role="keyword">using namespace</emphasis> boost::gregorian;
- date weekstart(<emphasis role="number">2002</emphasis>,Feb,<emphasis role="number">1</emphasis>);
- date weekend = weekstart + weeks(<emphasis role="number">1</emphasis>);
- date d2 = d1 + days(<emphasis role="number">5</emphasis>);
- date today = day_clock::local_day();
- if (d2 >= today) {} <emphasis role="comment">//date comparison operators</emphasis>
- date_period thisWeek(d1,d2);
- <emphasis role="keyword">if</emphasis> (thisWeek.contains(today)) {}<emphasis role="comment">//do something
- //iterate and print the week</emphasis>
- day_iterator itr(weekstart);
- <emphasis role="keyword">while</emphasis> (itr <= weekend) {
- std::cout << (*itr) << std::endl;
- ++itr;
- }
- <emphasis role="comment">//input streaming</emphasis>
- std::stringstream ss(<emphasis role="string">"2004-Jan-1"</emphasis>);
- ss >> d3;
- <emphasis role="comment">//date generator functions</emphasis>
- date d5 = next_weekday(d4, Sunday); <emphasis role="comment">//calculate Sunday following d4
- //US labor day is first Monday in Sept</emphasis>
- <emphasis role="keyword">typedef</emphasis> nth_day_of_the_week_in_month nth_dow;
- nth_dow labor_day(nth_dow::first,Monday, Sep);
- <emphasis role="comment">//calculate a specific date for 2004 from functor</emphasis>
- date d6 = labor_day.get_date(<emphasis role="number">2004</emphasis>);
- </programlisting>
- The following provides some example code using times.
- See <link linkend="date_time.posix_time">Time Programming</link>
- for more details.
- <programlisting><emphasis role="keyword">using namespace</emphasis> boost::posix_time;
- date d(<emphasis role="number">2002</emphasis>,Feb,<emphasis role="number">1</emphasis>); <emphasis role="comment">//an arbitrary date</emphasis>
- ptime t1(d, hours(<emphasis role="number">5</emphasis>)+nanosec(<emphasis role="number">100</emphasis>)); <emphasis role="comment">//date + time of day offset</emphasis>
- ptime t2 = t1 - minutes(<emphasis role="number">4</emphasis>)+seconds(<emphasis role="number">2</emphasis>);
- ptime now = second_clock::local_time(); <emphasis role="comment">//use the clock</emphasis>
- date today = now.date(); <emphasis role="comment">//Get the date part out of the time</emphasis>
- date tomorrow = today + date_duration(<emphasis role="number">1</emphasis>);
- ptime tomorrow_start(tomorrow); <emphasis role="comment">//midnight
- //input streaming</emphasis>
- std::stringstream ss(<emphasis role="string">"2004-Jan-1 05:21:33.20"</emphasis>);
- ss >> t2;
- <emphasis role="comment">//starting at current time iterator adds by one hour</emphasis>
- time_iterator titr(now,hours(<emphasis role="number">1</emphasis>));
- <emphasis role="keyword">for</emphasis> (; titr < tomorrow_start; ++titr) {
- std::cout << (*titr) << std::endl;
- }
- </programlisting>
- </para>
- <para>
- The following provides some example code using times.
- See <link linkend="date_time.local_time">Local Time Programming</link>
- for more details.
- <programlisting>
- <emphasis role="keyword">using namespace</emphasis> boost::local_time;
- <emphasis role="comment">//setup some timezones for creating and adjusting times
- //first time zone uses the time zone file for regional timezone definitions</emphasis>
- tz_database tz_db;
- tz_db.load_from_file(<emphasis role="string">"date_time_zonespec.csv"</emphasis>);
- time_zone_ptr nyc_tz = tz_db.time_zone_from_region(<emphasis role="string">"America/New_York"</emphasis>);
- <emphasis role="comment">//This timezone uses a posix time zone string definition to create a time zone</emphasis>
- time_zone_ptr phx_tz(new posix_time_zone(<emphasis role="string">"MST-07:00:00"</emphasis>));
- <emphasis role="comment">//local departure time in phoenix is 11 pm on April 2 2005
- // Note that New York changes to daylight savings on Apr 3 at 2 am)</emphasis>
- local_date_time phx_departure(date(<emphasis role="number">2005</emphasis>, Apr, <emphasis role="number">2</emphasis>), hours(<emphasis role="number">23</emphasis>), phx_tz,
- local_date_time::NOT_DATE_TIME_ON_ERROR);
- time_duration flight_length = hours(<emphasis role="number">4</emphasis>) + minutes(<emphasis role="number">30</emphasis>);
- local_date_time phx_arrival = phx_departure + flight_length;
- <emphasis role="comment">//convert the phx time to a nyz time</emphasis>
- local_date_time nyc_arrival = phx_arrival.local_time_in(nyc_tz);
- <emphasis role="comment">//2005-Apr-03 06:30:00 EDT</emphasis>
- std::cout << nyc_arrival << std::endl;
- </programlisting>
- </para>
-
- </section>
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