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.examples.flight"> 11 <title>Flight Time Example</title> 12 13 <para>This example shows a program that calculates the arrival time of a plane that flys from Phoenix to New York. During the flight New York shifts into daylight savings time (Phoenix doesn't because Arizona doesn't use dst).</para> 14 15<programlisting> 16<literal> 17<phrase role="preprocessor">#include</phrase><phrase role="string"> "boost/date_time/local_time/local_time.hpp"</phrase><phrase role="preprocessor"> 18#include</phrase><phrase role="special"> <</phrase><phrase role="identifier">iostream</phrase><phrase role="special">></phrase><phrase role="comment"> 19 20/* This example shows a program that calculates the arrival time of a plane 21 * that flys from Phoenix to New York. During the flight New York shifts 22 * into daylight savings time (Phoenix doesn't because Arizona doesn't use 23 * dst). 24 * 25 * 26 */</phrase><phrase role="keyword"> 27 28int</phrase><phrase role="identifier"> main</phrase><phrase role="special">()</phrase><phrase role="special"> 29{</phrase><phrase role="keyword"> 30 using</phrase><phrase role="keyword"> namespace</phrase><phrase role="identifier"> boost</phrase><phrase role="special">::</phrase><phrase role="identifier">gregorian</phrase><phrase role="special">;</phrase><phrase role="keyword"> 31 using</phrase><phrase role="keyword"> namespace</phrase><phrase role="identifier"> boost</phrase><phrase role="special">::</phrase><phrase role="identifier">local_time</phrase><phrase role="special">;</phrase><phrase role="keyword"> 32 using</phrase><phrase role="keyword"> namespace</phrase><phrase role="identifier"> boost</phrase><phrase role="special">::</phrase><phrase role="identifier">posix_time</phrase><phrase role="special">;</phrase><phrase role="comment"> 33 34 35 //setup some timezones for creating and adjusting local times 36 //This user editable file can be found in libs/date_time/data. 37</phrase><phrase role="identifier"> tz_database</phrase><phrase role="identifier"> tz_db</phrase><phrase role="special">;</phrase><phrase role="identifier"> 38 tz_db</phrase><phrase role="special">.</phrase><phrase role="identifier">load_from_file</phrase><phrase role="special">(</phrase><phrase role="string">"date_time_zonespec.csv"</phrase><phrase role="special">);</phrase><phrase role="identifier"> 39 time_zone_ptr</phrase><phrase role="identifier"> nyc_tz</phrase><phrase role="special"> =</phrase><phrase role="identifier"> tz_db</phrase><phrase role="special">.</phrase><phrase role="identifier">time_zone_from_region</phrase><phrase role="special">(</phrase><phrase role="string">"America/New_York"</phrase><phrase role="special">);</phrase><phrase role="comment"> 40 //Use a 41</phrase><phrase role="identifier"> time_zone_ptr</phrase><phrase role="identifier"> phx_tz</phrase><phrase role="special">(</phrase><phrase role="keyword">new</phrase><phrase role="identifier"> posix_time_zone</phrase><phrase role="special">(</phrase><phrase role="string">"MST-07:00:00"</phrase><phrase role="special">));</phrase><phrase role="comment"> 42 43 //local departure time in phoenix is 11 pm on april 2 2005 44 // (ny changes to dst on apr 3 at 2 am) 45</phrase><phrase role="identifier"> local_date_time</phrase><phrase role="identifier"> phx_departure</phrase><phrase role="special">(</phrase><phrase role="identifier">date</phrase><phrase role="special">(</phrase><phrase role="number">2005</phrase><phrase role="special">,</phrase><phrase role="identifier"> Apr</phrase><phrase role="special">,</phrase><phrase role="number"> 2</phrase><phrase role="special">),</phrase><phrase role="identifier"> hours</phrase><phrase role="special">(</phrase><phrase role="number">23</phrase><phrase role="special">),</phrase><phrase role="identifier"> 46 phx_tz</phrase><phrase role="special">,</phrase><phrase role="identifier"> 47 local_date_time</phrase><phrase role="special">::</phrase><phrase role="identifier">NOT_DATE_TIME_ON_ERROR</phrase><phrase role="special">);</phrase><phrase role="identifier"> 48 49 time_duration</phrase><phrase role="identifier"> flight_length</phrase><phrase role="special"> =</phrase><phrase role="identifier"> hours</phrase><phrase role="special">(</phrase><phrase role="number">4</phrase><phrase role="special">)</phrase><phrase role="special"> +</phrase><phrase role="identifier"> minutes</phrase><phrase role="special">(</phrase><phrase role="number">30</phrase><phrase role="special">);</phrase><phrase role="identifier"> 50 local_date_time</phrase><phrase role="identifier"> phx_arrival</phrase><phrase role="special"> =</phrase><phrase role="identifier"> phx_departure</phrase><phrase role="special"> +</phrase><phrase role="identifier"> flight_length</phrase><phrase role="special">;</phrase><phrase role="identifier"> 51 local_date_time</phrase><phrase role="identifier"> nyc_arrival</phrase><phrase role="special"> =</phrase><phrase role="identifier"> phx_arrival</phrase><phrase role="special">.</phrase><phrase role="identifier">local_time_in</phrase><phrase role="special">(</phrase><phrase role="identifier">nyc_tz</phrase><phrase role="special">);</phrase><phrase role="identifier"> 52 53 std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase><phrase role="special"> <<</phrase><phrase role="string"> "departure phx time: "</phrase><phrase role="special"> <<</phrase><phrase role="identifier"> phx_departure</phrase><phrase role="special"> <<</phrase><phrase role="identifier"> std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase><phrase role="identifier"> 54 std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase><phrase role="special"> <<</phrase><phrase role="string"> "arrival phx time: "</phrase><phrase role="special"> <<</phrase><phrase role="identifier"> phx_arrival</phrase><phrase role="special"> <<</phrase><phrase role="identifier"> std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase><phrase role="identifier"> 55 std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase><phrase role="special"> <<</phrase><phrase role="string"> "arrival nyc time: "</phrase><phrase role="special"> <<</phrase><phrase role="identifier"> nyc_arrival</phrase><phrase role="special"> <<</phrase><phrase role="identifier"> std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase><phrase role="special"> 56 57}</phrase> 58</literal> 59</programlisting> 60</section> 61