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Re: Accurate decimal numbers?
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Re: Accurate decimal numbers?


  • Subject: Re: Accurate decimal numbers?
  • From: John Stiles <email@hidden>
  • Date: Sat, 1 Jan 2005 11:36:55 -0800

You can get the same results with:

int
main () {
printf( "%f", atof("1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000") );
return 0;
}


On Jan 1, 2005, at 10:43 AM, mark wrote:

I don't allow "e" as a valid input character, so that case should be
covered…

From: John Stiles <email@hidden>
Date: Sat, 01 Jan 2005 09:44:39 -0800
To: mark <email@hidden>
Cc: Dev Cocoa <email@hidden>
Subject: Re: Accurate decimal numbers?

Don't be so sure :)

int main() {
printf( "%f", atof("1e500") );
}

[Session started at 2005-01-01 09:43:57 -0800.]
inf
Executable “atof” has exited with status 0.


On Jan 1, 2005, at 9:01 AM, mark wrote:

Thinking about it, you're correct. I thought I had a case, but the
more I
thought about it, the more it didn't make sense. In my case, I should
never
see infinity or NaN, as the number comes from a scan of a string, which
should reject anything that might cause a problem.

Thanks again,

mark

From: John Stiles <email@hidden>
Date: Fri, 31 Dec 2004 22:22:45 -0800
To: mark <email@hidden>
Cc: Dev Cocoa <email@hidden>, Brendan Younger
<email@hidden>
Subject: Re: Accurate decimal numbers?

In what case would "floor(x) == ceil(x)" return a different result
from
"floor(x) == x", exactly? I don't see how the ceil affects anything.
Also, I don't know if I 100% understand your last question. floor and
ceil return floats--they're typically* integral values, but still
float
types.

* Why "typically" and not "always"? Infinity and NaN.




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