From: Jim Cochrane <allergic-to-spam@...>
Date: 2006-11-27T03:30:09+09:00
Subject: Re: coding practise

On 2006-11-26, sempsteen <sempsteen@gmail.com> wrote:
> Yep, now i know that my Hash example is a different matter.
>
>> The fix:
>> change 'has_answer' to store the answer (privately) after calculating it and
>> 'answer' to simply retrieve that answer if it has been created.
>
> Where do you suggest to store the value for my amicable numbers example?

Looks like Paul has given you the answer (which I appreciate, since I
don't have the time to give a good answer).

>
> class Fixnum
>   def has_friend?
>     t1, t2 = 1, 1
>     2.upto(self / 2) {|i| t1 += i if self % i == 0}
>     2.upto(t1 / 2) {|i| t2 += i if t1 % i == 0}
>     return self == t2 && self != t1
>   end
>   def friend
>     t1, t2 = 1, 1
>     2.upto(self / 2) {|i| t1 += i if self % i == 0}
>     2.upto(t1 / 2) {|i| t2 += i if t1 % i == 0}
>     return t1 if self == t2 && self != t1
>   end
> end
>
> 1.upto(1000) {|i| print i, "\t<->\t", i.friend, "\n" if i.has_friend?}
>
> I want a "has_friend?" method and "friend" method. One for searching
> for the existing of given number, other one is for getting the value
> of the friend of that number. And i want those methods inside "Fixnum"
> class structure, like as instance methods.
> when i call has_friend? method it will store its value to some kind of
> variable, but return true or false and, when i call friend method it
> will get the stored value.
> But what must be that some kind of variable that holds the value?
> - class variable
> - instance variable
> - global
> - or what?
>


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