# dates_as_strings.cpp

Various parsing and output of strings.

    /*
    The following is a simple example that shows conversion of dates to and
    from a std::string.

    Expected output:
    2001-Oct-09
    2001-10-09
    Tuesday October 9, 2001
    An expected exception is next:
      Exception: Month number is out of range 1..12

    */

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

    int
    main()
    {

      using namespace boost::gregorian;

      try {
        // The following date is in ISO 8601 extended format (CCYY-MM-DD)
        std::string s("2001-10-9"); //2001-October-05
        date d(from_string(s));
        std::cout << to_simple_string(d) << std::endl;

        //Read ISO Standard(CCYYMMDD) and output ISO Extended
        std::string ud("20011009"); //2001-Oct-09
        date d1(from_undelimited_string(ud));
        std::cout << to_iso_extended_string(d1) << std::endl;

        //Output the parts of the date - Tuesday October 9, 2001
        date::ymd_type ymd = d1.year_month_day();
        greg_weekday wd = d1.day_of_week();
        std::cout << wd.as_long_string() << " "
               << ymd.month.as_long_string() << " "
               << ymd.day << ", " << ymd.year
               << std::endl;

        //Let's send in month 25 by accident and create an exception
        std::string bad_date("20012509"); //2001-??-09
        std::cout << "An expected exception is next: " << std::endl;
        date wont_construct(from_undelimited_string(bad_date));
        //use wont_construct so compiler doesn't complain, but you wont get here!
        std::cout << "oh oh, you should reach this line: "
               << to_iso_string(wont_construct) << std::endl;
      }
      catch(std::exception& e) {
        std::cout << "  Exception: " <<  e.what() << std::endl;
      }

      return 0;
    }