From: Brian Adkins <lojicdotcomNOSPAM@...>
Date: 2007-03-15T01:35:09+09:00
Subject: Re: Calculating the age given DOB

Clifford Heath wrote:
> Brian Adkins wrote:
>> (DateTime.now - birthdate) / 365.25
> 
> That's not very reliable. There are algorithms that calculate
> the number of days since some epoch from a date, and the
> reverse, based on Fortran code that was posted in the CACM
> sometime around 1970. I have a copy somewhere, but there
> must be a modern version already in Ruby. If you can't
> find a way, I'll dig out mine.
> 
> Just convert both dates to days-since-epoch and subtract.
> 
> Clifford.

Do you mind if I ask why you make the statement, "That's not very 
reliable." ? For what values of birthdate (an instance of Date) would 
the above expression not be "reliable" ?