From: sempsteen <sempsteen@...>
Date: 2006-11-27T05:04:08+09:00
Subject: Re: coding practise

Yes that's in my mind too. What i wrote was again a dirty, inefficient
code. I considered on the way you saw me. Here it is:

class AmicableNumbers
  def initialize(max = 1000)
    @numbers = Hash.new
    findFriends(max)
  end
  def findFriends(max)
    1.upto(max) do |j|
      t1, t2 = 1, 1
      2.upto(j / 2) {|i| t1 += i if j % i == 0}
      2.upto(t1 / 2) {|i| t2 += i if t1 % i == 0}
      @numbers.store(t1, t2) if j == t2 && t1 != j
    end
  end
  def has_friend?(number)
    return @numbers.has_key?(number)
  end
  def friend_of(number)
    return @numbers[number]
  end
end

amicable_numbers = AmicableNumbers.new(5000)
1.upto(5000) {|i| print i, "\t<->\t", amicable_numbers.friend(i), "\n"
if amicable_numbers.has_friend?(i)}

I know there are a lot of improvement points here but they are not so
important for me right now. I can improve later after constructing the
true structure.
In above example i have a class definition of amicable numbers. When i
call its constructer method with no arguments it finds the amicable
numbers within the range of 0..1000 and stores them at @numbers
instance variable. By "has_friend?" and "friend_of" methods i'm
looking for a friend number and getting the value of the friend number
for a given number.

I'll improve it or maybe write a new one and post it here as i gain
more info and experience on Ruby.

On 11/26/06, Paul Lutus <nospam@nosite.zzz> wrote:
> sempsteen wrote:
>
> > i did it, thanks again!
>
> Usenet is a door that swings both ways. This thread may last decades in
> Usenet archives and may be accessed again and again by students and others.
>
> What am I saying? I am saying you might consider posting your final code,
> for the benefit of all who might try to solve the same problem in the
> future.
>
> --
> Paul Lutus
> http://www.arachnoid.com
>
>