title: Time based on time zone in C++
body: <p>What is the difference between <code>gmtime()</code> and <code>localtime()</code> ?
  My requirement:
  I need to display the time as per the time zone of my place.
  I have a time in POSIX(UTC) format in seconds. i have time zone offset(between UTC and my current place) in seconds.
  I either add or subtract the time zone offset.
  After this i still have the time in POSIX format.
  In order to convert it to human time, should I use <code>gmtime()</code> or <code>localtime()</code>. this is because i need the date too.
  Please clarify.
  Thanks!</p>