From: GOTO Kentaro <gotoken@...>
Date: 2004-10-16T03:34:20+09:00
Subject: Re: Rounding to X digits

In message Re: Rounding to X digits
  on Thu, 14 Oct 2004 23:49:31 +0900, wrote "Robert Klemme":
> The difference in efficiency is one issue.  But there is a conceptual
> difference: it depends whether you want to align printed output or round a
> numeric value in a calculation.  For the first task sprintf is probably
> better because the amount of places printed is guaranteed (by the format
> string), while it's not if you just round the number and print it.

And there is an algorithmic difference: many implementation of 
sprintf(3) conform to ISO 31-0 but Float#round doesn't.

    puts 0.5.round             #=> 1
    puts sprintf("%.0f", 0.5)  #=> 0


Gotoken