boost完全开发指南第2章-处理时间3（日期date）

5、date

（1）创建日期

#include <iostream>

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

using namespaceboost::gregorian;

void create_date_obj_test()

{

date d1;

date d2(2010,1,1);

date d3(2013,Dec, 3);

date d4(d2);

assert(d1==date(not_a_date_time));

assert(d2!=d3);

assert(d2<d3);

//from string

date d5= from_string("2013-12-3");

date d6(from_string("2013/12/3"));

date d7= from_undelimited_string("20131203");

assert(d5==d6);

assert(d6==d7);

cout<<day_clock::local_day()<<endl;

cout<<day_clock::universal_day()<<endl;

}

（2）访问日期

#include <iostream>

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

using namespaceboost::gregorian;

void access_date_test()

{

date dt(2013,12,3);

cout<<dt.year()<<"-"<<dt.month()<<"-"<<dt.day()<<endl;

date::ymd_typeymd =dt.year_month_day();

cout<<"year="<<ymd.year<<endl;

cout<<"month="<<ymd.month<<endl;

cout<<"day="<<ymd.day<<endl;

cout<<"day_of_week:"<<dt.day_of_week()<<endl;

cout<<"day_of_year:"<<dt.day_of_year()<<endl;

cout<<"end_of_month:"<<dt.end_of_month()<<endl;

}

（3）日期的输出

#include <iostream>

#include <string>

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

using namespacestd;

using namespaceboost::gregorian;

void format_date_string_test()
{
date dt(2013,12,3);
//to_simple_string
std::stringsimple_str =to_simple_string(dt);
cout<<"to_simple_string:"<<simple_str<<endl;
//to_iso_string
string iso_str= to_iso_string(dt);
cout<<"to_iso_string:"<<iso_str<<endl;
//to_iso_extended_string
string iso_extend_str= to_iso_extended_string(dt);
cout<<"to_iso_extended_string:"<<iso_extend_str<<endl;

}

（4）与tm转换

void convert_to_tm_test()
{
date d(2013,12,3);
tm t = to_tm(d);
cout<<"tm.year: "<<t.tm_year<<" tm.month:"<<t.tm_mon<<" tm.day:"<<t.tm_mday<<endl;
date d_ = date_from_tm(t);
cout<<d_<<endl;
}

（5）日期长度

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

using namespace std;
using namespace boost::gregorian;
void date_duration_test()
{
days dd1(10), dd2(-100), dd3(255);
assert(dd1>dd2 && dd1 < dd3);
assert(dd1+dd2==days(-90));
assert((dd1+dd3).days()== 265);
assert(dd3/5==days(51));

weeks w(3);
assert(w.days()==21);

months m(2);
years y(1);

months m2= y+m;
assert(m2.number_of_months()==14);
assert((y*2).number_of_years()==2);
}

（6）日期运算

void date_calculate_test()
{
date d1(2012,1,1), d2(2013,1,8);

cout<<"d1: "<<d1<<" , d2: "<<d2<<endl;
cout<<"d2-d1:"<<d2-d1<<endl;

d1+=days(10);
cout<<"d1+=days(10): "<<d1.day()<<endl;

d1+=months(2);
cout<<"d1+=months(2) "<<d1.month()<<endl;

d1+=years(1);
cout<<"d1+=years(1) "<<d1.year()<<endl;
//d2
cout<<"d2-1week:";
d2-=weeks(1);
cout<<d2.day_of_week()<<","<<d2.week_number()<<endl;
}