title: How to manipulate dates/datetimes in c++11?
body: <p>This is embarrassing, but i am having a hard time doing simple manipulation of datetimes.</p>
  
  <p>This is the c# version of what i basically try to achive using c++11;</p>
  
  <pre class="lang-cs prettyprint-override"><code>DateTime date1=new DateTime(4,5,2012);
  DateTime date2=new DateTIme(7,8,2013);
  int day1=date1.Days;
  TimeSpan ts=d2-d1;
  int diffDays=ts.Days;
  </code></pre>
  
  <p>What did i try?</p>
  
  <pre class="lang-c prettyprint-override"><code>    std::tm tm;
      tm.tm_year=113;
      tm.tm_mon=0;
      tm.tm_wday=0;
  
      std::time_t tt=mktime(&amp;tm);
      std::chrono::system_clock::time_point then = std::chrono::system_clock::from_time_t(tt);
      std::chrono::system_clock::time_point now = std::chrono::system_clock::now();
      auto e1 = std::chrono::duration_cast&lt;std::chrono::hours&gt;(now - then).count();
  </code></pre>
  
  <p>The value of e1 (379218) makes no sense what so ever.</p>
  
  <p>I took a look at chrono, which is presented as the c++11 standard library for datetime but i just could not find an example of how to create a date having int year=2012, int month=2, int day=14.</p>
  
  <p>PS:Is chrono sufficient for handling date/times/timezones in c++11? Is there a need for time.h?</p>