Rounding off numbers

FROM : Johan Augustsson
DATE : Sat Jun 10 18:16:50 2006

Hi!

I have a problem when I round of numbers. My first question is if 
there aren't any smother way to round off an NSNumber. I do it like 
this:

myNbr is an NSNumber.
NSNumber *myRoundedNbr=[NSNumber numberWithDouble:[[NSString 
stringWithFormat:@"%.2f", [myNbr floatValue]] doubleValue]];



The bigger problem is that it doesn't round of correctly. Some tests 
show this:

Nbr            Rounded        
2.265     =>     2.27        OK
2.865     =>     2.87        OK
2.965    =>    2.96        WRONG

What can possibly be wrong and how do I solve it???

I use MacOS X 10.4.6
XCode 2.2