title: Converting dates from YY to YYYY --- how do compilers/interpreters know to use the correct century?
body: <p>I was just doing a bunch of importing of an old database, and as I was watching the results roll by, I wondered, how/why does it know to convert 12/31/13 to 12/31/2013, but 12/31/99 to 12/31/1999?  ("it" in this case is Python's strftime(%Y/%m/%d) function)</p>
  
  <p>What happens in 2050?  Will a record for 12/31/50 be interpreted by default as 2050, 1950, or 2150?</p>
  
  <p>I realize it may vary depending on language, and that there are probably flags/options to specifically force the use of a certain century.  But when you don't explicitly do so, what's making that judgment call by default?</p>