calendar.cpp

Example of using date_time functions for generating calendar for current year.

//
// Copyright (c) 2009-2011 Artyom Beilis (Tonkikh)
//
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
 
#include <boost/locale.hpp>
#include <ctime>
#include <iomanip>
#include <iostream>
 
int main()
{
    using namespace boost::locale;
 
    generator gen;
    std::locale::global(gen(""));
    std::cout.imbue(std::locale());
    // Setup environment
 
    boost::locale::date_time now;
 
    date_time start = now;
 
    // Set the first day of the first month of this year
    start.set(period::month(), now.minimum(period::month()));
    start.set(period::day(), start.minimum(period::day()));
 
    const int current_year = period::year(now);
 
    // Display current year
    std::cout << format("{1,ftime='%Y'}") % now << std::endl;
 
    // Run forward until current year is the date
    for(now = start; period::year(now) == current_year;) {
        // Print heading of month
        if(calendar().is_gregorian())
            std::cout << format("{1,ftime='%B'}") % now << std::endl;
        else
            std::cout << format("{1,ftime='%B'} ({1,ftime='%Y-%m-%d',locale=en} - {2,locale=en,ftime='%Y-%m-%d'})")
                           % now % date_time(now, now.maximum(period::day()) * period::day())
                      << std::endl;
 
        const int first = calendar().first_day_of_week();
 
        // Print week days
        for(int i = 0; i < 7; i++) {
            date_time tmp(now, period::day_of_week() * (first + i));
            std::cout << format("{1,w=8,ftime='%a'} ") % tmp;
        }
        std::cout << std::endl;
 
        const int current_month = now / period::month();
        const int skip = now / period::day_of_week_local() - 1;
        for(int i = 0; i < skip * 9; i++)
            std::cout << ' ';
        for(; now / period::month() == current_month; now += period::day()) {
            std::cout << format("{1,w=8,ftime='%e'} ") % now;
            if(now / period::day_of_week_local() == 7)
                std::cout << std::endl;
        }
        std::cout << std::endl;
    }
}