On Friday 24 July 2009, Manoj Chourasia wrote:
> |v1="128.015"
> |puts((v1.to_f*1000).to_i).to_s // giving 128014 instead of 128015
> |
> |Why the the result is rounding up to 128014 but the correct result
> |should be 128015.

I'm not an expert, but I think because when you write 128.015, the number you 
actually get is 128.0149999999999863575... (because 128.015 can't be 
represented as a number with a finite number of decimal digits in binary, just 
like, for example, 1/17 can't be repsented with a finite decimal number in 
decimal). You usually don't see this because by default only a small numberf 
decimal digits are shown, taking rounding into account. You can obtain a 
greater number of digits using, for example, format:

puts format("%.20f", 128.015)
=> 128.01499999999998635758

Now, when you multiply the number by 1000, what you actually get is: 
128014.99999999998544808477. And, since Float#to_i truncates the number (it 
doesn't round it), you get the number 128014.

I hope this helps

Stefano