From: "Shot (Piotr Szotkowski)" <shot@...>
Date: 2009-12-20T06:10:32+09:00
Subject: Re: Question about sum of fibonacci sequene [PROJECT EULER]

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jzakiya:

> Just a quick tip for you.

> To check for (odd/even)ness:

> Instead of doing this: if (c % 2 !=3D 0)
> which uses the modulo operator '%' which is
> "expensive" in terms of cpu cycles, because it
> performs (with a direct implementation) a (hardware)
> division operation, do this instead:

> # To check if integer c is even (true)
> if (c & 1 =3D=3D 0)

> # To check if integer c is odd (true)
> if (c & 1 =3D=3D 1)

Better yet, use
if c.even?
or
if c.even?
(which are both more readable and do the above binary checks in C).

=E2=80=94 Shot
--=20
To find a rhyme for silver,
A seemingly rhymeless rhyme,
Requires only will, ver-
bosity and time.
           [Willard R. Espy]

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