[Boost] boost time and date Processing-(2) time operations

<Start>

Next to boost, I will describe boost: datetime time processing. In C ++, the common time is time_t, filetime, and TM, while ptime is used in boost.

Construct ptime

1. ptime constructor has four types:

1:      using namespace boost::posix_time;

2:      using namespace boost::gregorian;

3: ptime Pt (date (2013, Jan, 24), time_duration (, 3); // constructed by date and time_duration

4: ptime pt1 (date (2013, Jan, 24), hours () + nanosec (5); // time_duration in the form of change can also be used

5: ptime pt2 (P1); // copy the constructor

6: ptime pt3 (neg_infin); // special value structure

7: ptime P; // default constructor, where p is not_a_date_time

2. Construct ptime with string:

1: STD: String ts1 ("23:32:22. 000"); // fixed format, supporting 6 digits after decimal point

2:  ptime pt1(time_from_string(ts1));

3: STD: String ts2 ("20130130t233222"); // Date and Time without Separators

4:  ptime pt2(from_iso_string(ts2));

5:  

3. Construct ptime by clock:

1:      ptime ct1(second_clock::local_time());

2:  ptime ct2(second_clock::universal_time());

3:  ptime ct3(microsec_clock::local_time());

4:  ptime ct4(microsec_clock::universal_time());

5:  

4. time_t and filetime construct ptime:

1: ptime T = from_time_t (TT); // Where TT is time_t

2: ptime T1 = from_ftime <ptime> (FT); // Where ft is filetime

Ptime access date and time

1:      using namespace boost::posix_time;

2:      using namespace boost::gregorian;

3:  ptime now(second_clock::local_time());

4:  std::cout << "today is: " << now.date() << std::endl;

5:  std::cout << "time is: " << now.time_of_day() << std::endl;

6:  

Ptime to string

1:      std::string now_str(to_simple_string(now));

2:  std::string now_iso_str(to_iso_string(now));

3:  std::string now_iso_ext_str(to_iso_extended_string(now));

4:  std::cout << now_str << std::endl;

5:  std::cout << now_iso_str << std::endl;

6:  std::cout << now_iso_ext_str << std::endl;

Mutual conversion between ptime and TM, time_t, and filetime

1. TM

 1:     using namespace boost::posix_time;

 2:     using namespace boost::gregorian;

 3:     tm pt_tm;

 4:     pt_tm.tm_year = 113;

 5:     pt_tm.tm_mon = 11;

 6:     pt_tm.tm_mday = 25;

 7:     pt_tm.tm_hour = 2;

 8:     pt_tm.tm_min = 23;

 9:     pt_tm.tm_sec = 40;

10:  

11:     ptime pt = data_from_tm(pt_tm);

12:     std::cout << pt << std::endl;

13:  

14:     pt = pt + hours(2);

15:     tm pt_tm1 = to_tm(pt);

2. time_t

 1:      using namespace boost::posix_time;

 2:      using namespace boost::gregorian;

 3:  

 4:  time_t now = time(NULL);

 5:  std::cout << "time_t : " << now << std::endl;

 6:  ptime now_pt = from_time_t(now);

 7:  std::cout << "ptime from time_t : " << now_pt.time_of_day() << std::endl;

 8:  tm* now_tm = gmtime(&now);

 9:  std::cout << "tm struct: hour : " << now_tm->tm_hour << std::endl;

10:  

3. filetime

1:      FILETIME ft;

2:  ft.dwHighDateTime = 29715317;

3:  ft.dwLowDateTime = 3865122988UL

4:      ptime pt = from_ftime<ptime>(ft);

5:  // pt ===> 2005-Jun-07 15:30:57.03958200

6:  

Time_duration and time_period

 1:      using namespace boost::posix_time;

 2:      using namespace boost::gregorian;

 3:  

 4:  time_duration td(100,200,3,9);

 5:  std::cout << td << std::endl;

 6:  date d(2013,Feb,5);

 7:  ptime pt(d,minutes(10));

 8:  ptime pt1(d,hours(10));

 9:  time_period tp(pt,pt1);

10:  std::cout << tp << std::endl;

11:  

For the difference between the two, one is the time interval, and the other is a window at the beginning and end of time. Time_duration is mainly used to calculate the Time Offset of ptime. Time_period can be used to calculate whether a ptime point is within this time range (refer to the contains function ). Time_period can be expanded after being created and can be translated. The functions are expand and shift. Please take a closer look.

The next article describes how to format the input and output of boost. datetime.

<CONCLUSION>

[Boost] boost time and date Processing-(2) time operations