From: Dirk Meijer <hawkman.gelooft@...>
Date: 2006-09-04T22:54:57+09:00
Subject: Re: Happy Numbers (#93)

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hi list,
my solution isn't short, and it isn't fast, only does base 10 (i didn't feel
up to it), and probably isn't very efficient.
but it _is_ a solution :-)
here is it:

------------------------------------
happynumbers.rb
 ------------------------------------
class Integer
  def happy?(show_sum=false)
    string=self.to_s
    passed=[self]
    sum=[]
    output=""

    loop do
      a=0
      0.upto(string.length-1) do |v|
        digit=string[v,1].to_i
        sum<<"#{digit}^2" if show_sum==true
        a+=digit * digit
      end
      if show_sum==true
        output<<sum.join(" + ")
        output<<" = #{a}\n"
      end

      if a==1
        output<<"\n#{self} is a happy number :)"
        return output
      end
      if passed.include?(a)
        output<<"\n#{self} is an unhappy number :("
        return output
      end

      string=a.to_s
      passed<<a
      sum=[]
    end
  end
end


if ARGV[0]==ARGV[0].to_i.to_s
  print ARGV[0].to_i.happy?(true)

elsif ARGV[0]=~/^upto\((\d+)\)$/
  count=0
  upto=$1.to_i
  1.upto(upto) do |p|
    text=p.happy?(false)
    print text
    count+=1 unless text=~/unhappy/
  end
  print "\n\n#{count} happy numbers upto #{upto}"

else
  puts "usage:"
  puts " ruby happynumbers.rb n"
  puts " ruby happynumbers.rb upto(n)"
end
------------------------------------
greetings, Dirk.

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