最近开了boost库的学习，就先从日期时间库开始吧，boost的date_time库是一个很强大的时间库，用起来还是挺方便的。以下算是我学习的笔记，我把它记录下来，以后便于我复习和查阅。

#include<iostream>
#include<boost/date_time/gregorian/greg_month.hpp>
#include<boost/date_time/gregorian/gregorian.hpp>

using namespace std;
using namespace boost;
using namespace boost::gregorian;

void timeDuration()

{

date d1;
        date d2(2010,1,1);
        date d3(2000,Jan,1);
        date d4(d2);
        if(d1==date(not_a_date_time))
        {
            cout<<"d1 is not a date time"<<endl;
        }
        if(d2==d4)
        {
            cout<<"d2 is eq to d4"<<endl;
        }
        if(d3<d4)
        {
            cout<<"d3 is before of d4"<<endl;
        }

        date t1(neg_infin);
        date t2(pos_infin);
        date t3(not_a_date_time);
        date t4(max_date_time);
        date t5(min_date_time);
        cout<<t1<<endl;
        cout<<t2<<endl;
        cout<<t3<<endl;
        cout<<t4<<endl;
        cout<<t5<<endl;

        date s1 = day_clock::local_day();
        date s2 = day_clock::universal_day();
        cout<<s1<<endl;
        cout<<s2<<endl;

        //date e1(1399,12,1);

        date::ymd_type ymd = s1.year_month_day();
        cout<<"year:"<<s1.year()<<endl;
        cout<<"month:"<<s1.month()<<endl;
        cout<<"day:"<<s1.day()<<endl;
    //
        cout<<"year:"<<ymd.year<<",month:"<<ymd.month<<",day:"<<ymd.day<<endl;
        cout<<"day_of_weeks:"<<s1.day_of_week()<<endl;
        cout<<"day_of_years:"<<s1.day_of_year()<<endl;
        cout<<"day_of_month:"<<s1.end_of_month()<<endl;

        boost::gregorian::greg_month gm(1);
        std::cout<<gm.as_short_string()<<endl;

        std::cout << to_simple_string(s1) << std::endl;
        std::cout << to_iso_string(s1) << std::endl;
        std::cout<<to_iso_extended_string(s1)<<endl;

        tm tm1 = to_tm(s1);
        cout<<"year:"<<tm1.tm_year<<",month:"<<tm1.tm_mon<<",day:"<<tm1.tm_mday <<endl;

        d1 = date_from_tm(tm1);
        cout<<d1<<endl;

        days dd1(10),dd2(-100),dd3(255);

        cout<<dd1<<" "<<dd2<<" "<<dd3<<endl;


    /*日期的运算*/
        date ddd1(2000,1,1),ddd2(2008,8,8);
        cout<<ddd2-ddd1<<endl;   //结果是天数
        cout<<(ddd1+=days(100))<<endl;
        cout<<(ddd1+=years(8))<<endl;
    /*日期区间*/
        date_period dp1(date(2010,1,1),days(200));
        date_period dp2(date(2010,1,1),date(2009,1,1));
        date_period dp3(date(2010,1,1),date(2014,1,1));
        cout<<dp1<<endl;
        cout<<dp2<<endl;
        cout<<dp3<<endl;
        cout<<dp1.begin()<<"--"<<dp1.end()<<endl;

        dp1.shift(days(100));
        cout<<dp1<<endl;
        dp1.expand(days(3));
        cout<<dp1<<endl;
        if(dp1.is_after(d1))
        {
            cout<<"dp1 is after d1"<<endl;
        }
        else cout<<"dp1 is before d1"<<endl;

        d1 = date(2014,7,27);
        d2 = d1 + days(10);

        day_iterator d_iter(d1);
        for(; d_iter<=d2 ; ++d_iter)
        {
            cout<<*d_iter<<endl;
        }
        date d_start(s1.year(),s1.month(),1);
        date d_end = s1.end_of_month();

        for(day_iterator d_iter(d_start);d_iter!=d_end;++d_iter)
        {
            cout<<*d_iter<<" "<<d_iter->day_of_week()<<endl;
        }

        date birth(2008,11,20);
        date d18years = birth + years(18);
        cout<<d18years << " is " << d18years.day_of_week()<<endl;

        int count = 0;
        for(day_iterator d_iter(date(d18years.year(),11,1));d_iter!=d18years.end_of_month();++d_iter)
        {
            if(d_iter->day_of_week()==Sunday) ++count;
        }
        cout<<"total "<<count<<" Sundays."<<endl;
        count = 0;
        for(month_iterator m_iter(date(d18years.year(),1,1));m_iter<date(d18years.year()+1,1,1);++m_iter)
        {
            count += m_iter->end_of_month().day();
        }
        cout<<"total "<<count<<"days of year."<<endl;

    typedef gregorian_calendar gre_cal;

        cout<<(gre_cal::is_leap_year(d18years.year()) ? 365 : 366)<<endl;

/*时间长度操作*/

    time_duration td(1,20,30,1000);//1小时20分30秒1毫秒

    hours h(1);   //1小时

    minutes m(10);  //10分钟

    seconds s(30);  //30秒

    millisec ms(1); //1毫秒

    time_duration td1 = h + m + s +  ms;  //可以直接赋值

    time_duration td2 = duration_from_string("1:10:30:001");//从字符串创建

    int nHour = td1.hours();  //小时

    int nMin = td1.minutes(); //分钟

    int nSec = td1.seconds(); //秒数

    long nMic = td1.fractional_seconds();  //微妙数

    int total_seconds = td1.total_seconds(); //总秒数

    time_duration::tick_type total_milliseconds = td1.total_milliseconds(); //总毫秒数

    time_duration::tick_type total_microseconds = td1.total_microseconds(); //总微妙数

    hours h1(-10);

    if(h1.is_negative()) cout<<"h1 is negative"<<endl;  //可以是负值

    time_duration td3 = h1.invert_sign();  //改变时间长度符号

    cout<<td3<<endl;

    /*时间长度的特殊值*/

    time_duration td4(not_a_date_time);

    if(td4.is_special() && td4.is_not_a_date_time())

        cout<<"td4 is a special and not a date time"<<endl;

    time_duration td5(neg_infin); //负无限

    if(td5.is_special() && td5.is_neg_infinity())

        cout<<"td5 is a special and is a negative infinity time"<<endl;

    /*时间长度的比较*/

    time_duration td6 = hours(1);

    time_duration td7 = hours(1) + minutes(30);

    if(td6 < td7) cout<<"dt6 < td7"<<endl;

    if((td6+td7).hours()==3) cout<<"(td6+td7).hours() is 3"<<endl;

    if((td1-td7).is_negative()) cout<<"(td6-td7) is negative"<<endl;

    if((td6/2).minutes()==td7.minutes())cout<<"(td6/2).minutes == td7.minutes"<<endl;

    time_duration td8(1,20,30,1000);

    cout<<to_simple_string(td8)<<endl;

    cout<<to_iso_string(td8)<<endl;

    tm tm1 = to_tm(td8);  //转换到tm结构

    /*date_time 库的默认的时间精度是微妙，当定义了BOOST_DATE_TIME_POSIX_TIME_STD_CONFIG

     时间的精度就发生了变化*/

//#define BOOST_DATE_TIME_POSIX_TIME_STD_CONFIG  //定义纳秒精度宏

    time_duration td9(1,10,30,1000); //1000纳秒

    cout<<td9<<endl;

    cout<<td9.fractional_seconds()<<endl;  //返回秒的小数部分，此处返回的时纳秒

    if(time_duration::unit()*1000*1000*1000== seconds(1))//时间计量的最小单位

    {

        cout<<"精度为1纳秒"<<endl;

    }

    else

    {

        cout<<"精度为1微妙"<<endl;

    }

    if(td9.resolution() == boost::date_time::nano) cout<<"精度为1纳秒"<<endl;

    cout<<"秒的小数部分的位数："<<td9.num_fractional_digits()<<endl;

    time_duration::tick_type my_millisec = time_duration::ticks_per_second()/1000;

    time_duration td10(1,10,20,10*my_millisec);  //10毫秒

    /*时间点*/

    ptime p(boost::gregorian::date(2010,3,5), time_duration(15,55,30,0));   //日期+时间段组成一个时间点

    ptime p1 = time_from_string("2014-7-29 16:00:30");  //从字符串创建时间点

    ptime p2 = second_clock::local_time();    //当前本地时间

    ptime p3 = microsec_clock::universal_time(); //获取UTC时间

    cout<<p2<<" "<<p3<<endl;

    /*时间点与tm、time_t结构转换*/

    tm t = to_tm(p1);

    cout<<"tm.year:"<<t.tm_year<<",tm.month"<<t.tm_mon<<",tm.day"<<t.tm_mday<<endl;

    date dt = date_from_tm(t);

    time_duration td11(t.tm_hour,t.tm_min,t.tm_sec);

    ptime p4 = ptime(dt,td11);

    p4 = from_time_t(std::time(0));

    if(p4.date()==day_clock::local_day()) cout<<"p4.day == day_clock::day"<<endl;

    /*时间区间*/

    ptime p5(date(2010,1,1),hours(12));

    time_period tp1(p5,hours(8)); //时间点+区间长度

    time_period tp2(p5+hours(8),hours(1));

    if(tp1.end() == tp2.begin() && tp1.is_adjacent(tp2)) cout<<"tp1 and tp2 is adjacent"<<endl;

    if(tp1.intersects(tp2)) cout<<"tp1和tp2相交"<<endl;

    tp1.shift(hours(10)); /*tp1向后平移了一小时*/;

    if(tp1.is_after(p5)) cout<<"tp1 在 tp5 之后"<<endl;

    tp2.expand(hours(2)); /*tp2向两端扩展2小时*/

    if(tp1.contains(tp2)) cout<<"tp1 包含 tp2"<<endl;

    /*时间迭代器*/

    ptime p6(date(2010,2,27),hours(10));

    for(time_iterator iter(p,minutes(10));iter < p+hours(1); ++iter) /*时间点+步长*/

    {

        cout<<*iter<<endl;

    }

    /*时间的格式化*/

    date d(2010,3,6);

    date_facet * dfacet = new date_facet("%Y年%m月%d日");

    cout.imbue(locale(cout.getloc(),dfacet));

    cout<<d<<endl;

    time_facet * tfacet = new time_facet("%Y年%m月%d日%H点%M分%S%F秒");

    cout.imbue(locale(cout.getloc(),tfacet));

    cout<<ptime(d,hours(21)+minutes(50)+millisec(100))<<endl;

    /*本地时间*/

    tz_database tz_db;   //时区数据库对象

    {

        boost::timer t;

        tz_db.load_from_file("./date_time_zonespec.csv");

    }

    cout<<endl;

    time_zone_ptr shz = tz_db.time_zone_from_region("Asia/Shanghai");  //获取上海时区，即北京时间

    time_zone_ptr nyz = tz_db.time_zone_from_region("America/New_York"); //获取纽约时区

    cout<<shz->has_dst()<<endl;    //是否有夏令时

    cout<<shz->std_zone_name()<<endl;  //上海市区的名称

    local_date_time dt_bj(date(2008,1,7),   //北京时间 2008 1 7

                          hours(12),     //中午12点

                          shz,  //上海时区

                          false //无夏令时

                          );

    time_duration flight_time = hours(15);  //飞行15小时

    dt_bj += flight_time;  //到达的北京时间

    cout<<dt_bj<<endl;

    local_date_time dt_ny = dt_bj.local_time_in(nyz); //转化为纽约时间

    cout<<dt_ny<<endl;

}