From: Rob Biedenharn <Rob@...>
Date: 2010-01-19T09:17:00+09:00
Subject: Re: Return class as Integer

On Jan 18, 2010, at 7:05 PM, lalawawa wrote:

> Gary Wright wrote:
>> On Jan 18, 2010, at 5:03 PM, Atheeq Pasha wrote:
>>> hello,
>>>
>>> Can anyone tell me how to get a return class as Integer in ruby?
>>>
>>> and to use Integer.new method with parameter as a number.
>> Integer is an abstract class is Ruby.  You want a Fixnum
>> (32 bit integers) or a Bignum (arbitrarily large integers).
>> Fixnum and Bignum are subclasses of Integer.  Just use regular
>> decimal notation to 'generate' fixnums and bignums instances.
>>>> 42.class
>> => Fixnum
>>>> 4200000000.class
>> => Bignum
>> Gary Wright
>
> I don't think Fixnums are 32 bit.
>
> irb(main):008:0> (1 << 30).class
> => Bignum
> irb(main):009:0> (1 << 29).class
> => Fixnum
> irb(main):010:0>
>
> This is on Ubuntu Linux.
>


No, but they're close enough. There's a few bits used to identify some  
immediate values in the MRI implementation. On a 64-bit platform, a  
Fixnum will be used up to (1 << 62 - 1). The difference tends to  
matter only when you're trying to do true 32-bit (or 64-bit) things  
like cryptographic algorithms where bit shifts or bit rotations are  
defined on an exact word size.

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob@AgileConsultingLLC.com