Sat, Nov 02, 2013, Mischa Baars:
> On 11/02/2013 11:19 PM, Jonathan Wakely wrote:
> >On 2 November 2013 22:12, Mischa Baars wrote:
> >
> >And 1.1 is not representable as long double.
> >
> >If you are willing to stop being so arrogant for a few minutes and
> >learn something try running this program and think about what the
> >result means:
> >
> >#include <assert.h>
> >
> >int main()
> >{
> > long double l = 1.1;
> > long double ll = 10 * l;
> > assert( ll == 11 );
> >}
> >
> >If you think GCC gets this result wrong then please use a different
> >compiler and stop wasting everyone's time, this is off-topic for this
> >mailing list.
>
> There's no converting to any string in your example. You only
> convert source code strings into their corresponding doubles.
>
> What I'm trying to point out is that the output differs from the
> value entered in the source. The string 1.1 from the source is not
> correctly converted to it's corresponding double, or the double is
> not correctly converted back into it's corresponding string.
I challenge you to come up with a better way of representing floating
point numbers in an efficient manner _and_ support silly edge cases like
imperfectly representable numbers. Read up on IEEE floats, particularly
that link Jonathan posted earlier.
But please stop wasting everyones' time. Clang exhibits the same
behaviour, it's not a compiler issue.
Thank you
