cast(int) getting an unexpected number
Ali Cehreli
acehreli at yahoo.com
Wed Nov 4 12:32:53 PST 2009
Ok, I messed up my previous comment while moving rmcguire's lines around. Trying again... Also, I am not sure about the last bit now. :)
rmcguire Wrote:
> why is this not a compiler bug?
> because:
> import std.stdio;
>
> void main() {
> float f=0.01;
Just an information: 0.01 is double, there is type conversion there.
> writefln("%0.2f->%d",f,cast(int)(f*100f));
> results in:
> 0.01->0
f*100f is represented to be less than 0.
> writefln("%0.2f->%d",f,cast(int)(.01*100f));
> results in:
> 0.01->1
.01 * 100f is double and apparently represented as something more than 1.
> writefln("%0.2f->%f",f,(f*100f));
> results in:
> 0.01->1.000000
If it's like in C, floating point values must be passed as double arguments to functions. So there is float-to-double conversion before the function call, effectively representing the argument as double.
Ali
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