Is this how to program an algorithm which uses modular arithmatic?

Question

if ( (x-a)^n is not (x^n-a) (mod x^r-1,n) ) then output COMPOSITE
from [http://primes.utm.edu/prove/prove4_3.html|http://primes.utm.edu/prove/prove4_3.html]
a, n, and r are define variables. x is part of a polynomial (I'll use this to handle the polynomial type variables). My question is, how do I program for modular arithmetic? Does this do what the above pseudocode does?
[ (x-a)^n]-[(x^n-a)]% (x^r-1) != 0 && [ (x-a)^n]-[(x^n-a)]% (n) != 0
I know that a=b(mod x) means a-b is a multiple of x. Therefore I reason the above statment is correct. I assume the coma in the (mod x^r-1,n) means that (x-a)^n is neither congruent to x^r-1 nor congruent to a.
I'd just try this out to see if it works, but if it doesn't then I wouldn't be sure if it's this piece of code, or another problem in my program which I causing problems. That's why I ask. Plus if this isn't the way it works then I have no clue how to do this.
Thanks a lot people

Answer 1

ok I'm going to emberass myself with this question now. I read the [API for polynomails|http://www.control.lth.se/~kurstr/InternDator/java/regler/se/lth/control/algorithms/Polynomial.html#Polynomial(int,%20double[])] and I can't figure out how to use the polynomials in a program. i.e. I go:
import se.lth.control.algorithms.BasePolynomial;and when I compile I get the error "package se.lth.control.algorithms.BasePolynomial does not exits". What do I do now? I know this is a lame question, but I basically taught myself that I import whatever is written at the top beneath the bold faced type, when reading the classes API. Anyone want to clue me in on how stuff actually works?
Edited by: bean-planet on Jul 17, 2008 4:33 PM
Oh I see now, that's not actually part of Sun's website, it only looks similar. I guess that would explain why the package didn't come with the IDE I'm using. Am I write or just more confused? Can anyone figure out how to download the package so that I can actually use it?
Edited by: bean-planet on Jul 17, 2008 7:13 PM