3.1 finding today's date

Problem

You need to find the year, month day values for today's date.

Solution

Using Boost date-time this can be easily achieved.

//get easy access to the needed types
#include <boost/date_time.hpp>
using boost::gregorian::date;
using boost::gregorian::day_clock;
using boost::gregorian::greg_year_month_day;
using std::cout;
using std::endl;

//read the clock with local time adjustment according to computer settings
date d = day_clock::local_day();

//extract the year month day values
date::ymd_type ymd = d.year_month_day();

After extracting the year month day the information can be printed. Note that the month is a special type in the ymd_type that will print as a string -- so the following will print something like 2013-May-13

cout << "The current date is :"  << ymd.year << "-" 
     << ymd.month << "-" << ymd.day << endl; 

If you want the month as a number then call as_number on the month

cout << "The current date is :"  << ymd.year << "-" 
     << ymd.month.as_number() << "-" << ymd.day << endl; 

In boost date-time you can also use local based i/o on the date type directly

cout.imbue(std::locale(cout.getloc(), new boost::gregorian::date_facet("%Y %m %d")));
cout << "The current date using faceted date output:" << d << endl; //2013 05 13

Discussion

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