cast(int) getting an unexpected number

[Charles Hixson]

Lars T. Kyllingstad wrote:
> Michal Minich wrote:
>> Hello rmcguire,
>>
>>> why is this not a compiler bug?
>>> because:
>>> import std.stdio;
>>> void main() {
>>> float f=0.01;
>>> writefln("%0.2f->%d",f,cast(int)(f*100f));
>>> writefln("%0.2f->%d",f,cast(int)(.01*100f));
>>> writefln("%0.2f->%f",f,(f*100f));
>>> }
>>> results in:
>>> 0.01->0
>>> 0.01->1
>>> 0.01->1.000000
>>> I would say something is dodgy.
>>>
>>> -Rory
>>>
>>
>> I think this may be case of:
>> At comple time floating point computations may be done at a higher
>> precision than run time.
>
>
> Yes, if you do this:
>
> float f = 0.01;
> float g = f * 100f;
> real r = f * 100f;
> writeln("%s, %s, %s", f, cast(int) g, cast(int) r);
>
> you get:
>
> 0.01, 0, 1
>
> I believe just writing cast(int)(f*100f) is more or less the same as the
> 'real' case above.
>
> -Lars
Can that *really* be the explanation??  I know that float doesn't have 
all that much precision, but I thought it was more than 5 or 6 
places...and this is, essentially, two places.