# time_math.cpp

Various types of calculations with times and time durations.

    //Some simple examples of constructing and calculating with times
    //Output:
    //2002-Feb-01 00:00:00 - 2002-Feb-01 05:04:02.001000000 = -5:04:02.001000000

    #include "boost/date_time/posix_time/posix_time.hpp"
    #include <iostream>

    int
    main()
    {
      using namespace boost::posix_time;
      using namespace boost::gregorian;

      date d(2002,Feb,1); //an arbitrary date
      //construct a time by adding up some durations durations
      ptime t1(d, hours(5)+minutes(4)+seconds(2)+millisec(1));
      //construct a new time by subtracting some times
      ptime t2 = t1 - hours(5)- minutes(4)- seconds(2)- millisec(1);
      //construct a duration by taking the difference between times
      time_duration td = t2 - t1;

      std::cout << to_simple_string(t2) << " - "
             << to_simple_string(t1) << " = "
             << to_simple_string(td) << std::endl;

      return 0;
    }