3.3 converting epoch seconds to dmyhms

Problem

Given a number of seconds since the epoch date, calculate the year, month, day, hour, minute and second.

Solution

Boost DateTime makes this very easy. You create a boost::posix_time::ptime from the epoch seconds, and then extract the information that you want from that.

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

using namespace boost::posix_time;
using namespace boost::gregorian;

int main ( int, char ** ) {
    std::time_t t1(1368454200);  // May 13, 2013 2:10 PM
    ptime pt = from_time_t(t1);
//  Split into date and time parts
    time_duration td = pt.time_of_day ();
    date d = pt.date ();
	 
//  Extract the bits
    std::cout << "Date: " << d.year () << ' ' << d.month () << ' ' << d.day ()
        << ' ' << td.hours() << ':' << td.minutes() << ':' << td.seconds()
        << std::endl;
	
    return 0;
    }

This should produce the output Date: 2013 May 13 14:10:0