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| <!DOCTYPE library PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN" |
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| |
| <!-- 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> |