[ruby-talk:7846] Re: Next amusing problem: talking integers (was Re: Code sample for improvement)

David Alan Black <[e-mail]> wrote:
> On Wed, 20 Dec 2000, Stephen White wrote:
> 
> > Hopefully this code dissection, rewriting and optimisation becomes a
> > regular feature. Anyone else want to post the next amusing problem
> > for us to work on? :)
> 
> Just wait til the online cookbook is up and running :-)
> 
> Meanwhile -- well, am I allowed to do the cowardly thing, and
> pose this as a puzzle, without actually having done it yet?  I did
> do it in Perl, but am curious to see ideas for it in Ruby.
> 
> Namely......
> 
> Input:   123456
> Output:  "one-hundred twenty-three thousand four-hundred fifty-six"

irb(main):001:0> load 'numreader.rb'
true
irb(main):002:0> NumReader::English.say(123456)
"one hundred twenty-three thousand four hundred fifty-six"
irb(main):003:0> NumReader::English.say(-42111000404
irb(main):004:1> )
"negative forty-two billion one hundred eleven million four hundred four"

The problem is that originally I had a NumReader::French (module) and 
included that from NumReader::English (module), but I need to rethink how 
the constants would be set and overridden.

#!/usr/local/bin/ruby
module NumReader
    module English
        NEGATIVE = "negative"
        n = %w(zero one two three four five six seven eight nine
          ten eleven twelve thirteen)
        NUMBERS = n +
          (4 .. 9).collect {|num| n[num] + "teen"}
        TENS = [nil, nil] + %w(twenty thirty forty fifty sixty seventy eighty
          ninety)
        HUNDRED = "hundred" 
        ORDERS_OF_3 = [""] + %w(thousand million billion trillion zillion
          quadrillion quintillion sextillion septillion octillion nonillion
          decillion undecillion duodecillion tredecillion quattuordecillion
          quindecillion sexdecillion septendecillion octodecillion
          novemdecillion vigintillion)
        def English.say(num)
            num = num.to_i
            if num < 0
                num = -num
                negative = true
            else
                negative = false
            end
            return NUMBERS[0].dup if num.zero?
            answer = []
            i = 0
            while num > 0
                x = num % 1000
                if x.nonzero?
                    f = less_than_1000(x)
                    if i != 0
                        answer.push([f, ORDERS_OF_3[i]])
                    else
                        answer.push(f)
                    end
                end
                i += 1
                num /= 1000
            end
            answer.push(NEGATIVE) if negative
            answer.reverse.join(" ")
        end
        private
        def English.less_than_100(num)
            case num
                when 0 .. 19
                    NUMBERS[num]
                when 20 .. 99
                    units = num % 10
                    if units.nonzero?
                        TENS[num / 10] + "-" + NUMBERS[units]
                    else
                        TENS[num / 10]
                    end
                else
                raise ArgumentError, "number not between 0 and 99"
            end
        end
        def English.less_than_1000(num)
            hundreds = num / 100
            if hundreds.nonzero?
                NUMBERS[hundreds] + " " + HUNDRED +
                  ((num % 100).nonzero? ? " " + less_than_100(num % 100) : "")
            else
                  less_than_100(num % 100)
            end
        end
    end
end

--
 Brian Fundakowski Feldman           \  FreeBSD: The Power to Serve!  /
 [e-mail]                    `------------------------------'