Re: print and floating point output

[Matthias Kopfermann <matthi@infodrom.north.de>]

On Tue, May 11, 2004 at 01:01:06PM +0100, Peter Stephenson wrote:

> Well, the alternative is silently censoring decimal places, many of
> which may be valid.  If you want something smart to guess how many
> places are valid, you need to write it.

So you think that ruby, perl and python censor output?
I think that's just useful and uses the principle of least
surprise.

>   typeset -E 8 var
> 
> then
> 
>   (( var = 2.8 * 16.0 ))
>   print $var
> 
> for a given number of decimal places.  Or use printf, which does it's
> own conversion:

I know about printf and typeset already. I just thought that
perl, ruby and python have good points in their decision,
too. :)

And what's the way of using typeset with something like
print $((2.8*16.0)) ?


plus, bc does it that way, too.
and i don't think that bc does censor my output at all.
Well, to a point there always is censoring with floating
point, ack!

> 
> % printf "%f\n" $((2.8*16.0))
> 44.800000

Why is that no censoring then?

> 
> If you are doing serious floating point work, unfortunately you need to
> understand something about rounding errors, which are a tricky and
> ever-present feature.

I learned that here.

        Matthias