J-Scag · October 11, 2013 14:12
diff --git a/roman_numerals.rb b/roman_numerals.rb
 # # Roman Numerals

 # The Romans were a clever bunch. They conquered most of Europe and
 # ruled it for hundreds of years. They invented concrete and straight
 # roads and even bikinis. One thing they never discovered though was 
 # the number zero. This made writing and dating extensive histories
 # of their exploits slightly more challenging, but the system of
 # numbers they came up with is still in use today. For example the
 # BBC uses Roman numerals to date their programmes.

 # The Romans wrote numbers using letters - I, V, X, L, C, D, M.
 # (notice these letters have lots of straight lines and are hence
 # easy to hack into stone tablets).

 # Write a function to convert from normal numbers to
 # Roman Numerals: e.g.

 # ```
 #  1  => I
 # 10  => X
 #  7  => VII
 # ```

 # There is no need to be able to convert numbers larger than about
 # 3000. (The Romans themselves didn't tend to go any higher)

 # Wikipedia says: Modern Roman numerals ... are written by
 # expressing each digit separately starting with the left most
 # digit and skipping any digit with a value of zero.

 # To see this in practice, consider the example of 1990.

 # In Roman numerals 1990 is MCMXC:

 # 1000=M
 # 900=CM
 # 90=XC

 # 2008 is written as MMVIII:

 # 2000=MM
 # 8=VIII

 # See also: http://www.novaroma.org/via_romana/numbers.html

 class Integer


  ROMAN = ["I","X","C","M"]
  FIVES = ["V","L","D"]

  def to_roman
    converter = self.to_s.reverse.chars
    romanized = converter.each_with_index.collect do |num,dex|
      roman_converter(num, dex)
    end
    romanized.join("").reverse
  end


  def roman_converter(dec, place)
    if dec == "9"
      numeral = "#{ROMAN[place+1]}#{ROMAN[place]}"
    elsif place < 3 && dec.to_i.between?(4,8)
      fives(dec, place)
    else
      ROMAN[place] * dec.to_i
    end
  end

  def fives(dec, place)
    return FIVES[place] if dec == "5"
    return "#{ROMAN[place]}#{FIVES[place]}" if dec == "6"
    return "#{FIVES[place]}#{ROMAN[place]}" if dec == "4"
    return "#{ROMAN[place]*2}#{FIVES[place]}" if dec == "7"
    return "#{ROMAN[place]*3}#{FIVES[place]}" if dec == "8"
  end

 end

 RSpec.configure do |config|
  # Use color in STDOUT
  config.color_enabled = true

  # Use color not only in STDOUT but also in pagers and files
  config.tty = true

  # Use the specified formatter
  config.formatter = :progress # :progress, :html, :textmate
 end

 describe Integer, '#to_roman' do

  it 'converts 1' do
    1.to_roman.should eq 'I'
  end

  it 'converts 2' do
    2.to_roman.should eq 'II'
  end

  it 'converts 3' do
    3.to_roman.should eq 'III'
  end

  it 'converts 4' do
    4.to_roman.should eq 'IV'
  end

  it 'converts 5' do
    5.to_roman.should eq 'V'
  end

  it 'converts 6' do
    6.to_roman.should eq 'VI'
  end

  it 'converts 9' do
    9.to_roman.should eq 'IX'
  end


  it 'converts 27' do
    27.to_roman.should eq 'XXVII'
  end

  it 'converts 48' do
    48.to_roman.should eq 'XLVIII'
  end

  it 'converts 59' do
    59.to_roman.should eq 'LIX'
  end

  it 'converts 93' do
    93.to_roman.should eq 'XCIII'
  end

  it 'converts 141' do
    141.to_roman.should eq 'CXLI'
  end

  it 'converts 163' do
    163.to_roman.should eq 'CLXIII'
  end

  it 'converts 402' do
    402.to_roman.should eq 'CDII'
  end

  it 'converts 575' do
    575.to_roman.should eq 'DLXXV'
  end

  it 'converts 911' do
    911.to_roman.should eq 'CMXI'
  end

  it 'converts 1024' do
    1024.to_roman.should eq 'MXXIV'
  end

  it 'converts 3000' do
    3000.to_roman.should eq 'MMM'
  end

 end
	# # Roman Numerals

	# The Romans were a clever bunch. They conquered most of Europe and
	# ruled it for hundreds of years. They invented concrete and straight
	# roads and even bikinis. One thing they never discovered though was
	# the number zero. This made writing and dating extensive histories
	# of their exploits slightly more challenging, but the system of
	# numbers they came up with is still in use today. For example the
	# BBC uses Roman numerals to date their programmes.

	# The Romans wrote numbers using letters - I, V, X, L, C, D, M.
	# (notice these letters have lots of straight lines and are hence
	# easy to hack into stone tablets).

	# Write a function to convert from normal numbers to
	# Roman Numerals: e.g.

	# ```
	# 1 => I
	# 10 => X
	# 7 => VII
	# ```

	# There is no need to be able to convert numbers larger than about
	# 3000. (The Romans themselves didn't tend to go any higher)

	# Wikipedia says: Modern Roman numerals ... are written by
	# expressing each digit separately starting with the left most
	# digit and skipping any digit with a value of zero.

	# To see this in practice, consider the example of 1990.

	# In Roman numerals 1990 is MCMXC:

	# 1000=M
	# 900=CM
	# 90=XC

	# 2008 is written as MMVIII:

	# 2000=MM
	# 8=VIII

	# See also: http://www.novaroma.org/via_romana/numbers.html

	class Integer


	ROMAN = ["I","X","C","M"]
	FIVES = ["V","L","D"]

	def to_roman
	converter = self.to_s.reverse.chars
	romanized = converter.each_with_index.collect do \|num,dex\|
	roman_converter(num, dex)
	end
	romanized.join("").reverse
	end


	def roman_converter(dec, place)
	if dec == "9"
	numeral = "#{ROMAN[place+1]}#{ROMAN[place]}"
	elsif place < 3 && dec.to_i.between?(4,8)
	fives(dec, place)
	else
	ROMAN[place] * dec.to_i
	end
	end

	def fives(dec, place)
	return FIVES[place] if dec == "5"
	return "#{ROMAN[place]}#{FIVES[place]}" if dec == "6"
	return "#{FIVES[place]}#{ROMAN[place]}" if dec == "4"
	return "#{ROMAN[place]*2}#{FIVES[place]}" if dec == "7"
	return "#{ROMAN[place]*3}#{FIVES[place]}" if dec == "8"
	end

	end

	RSpec.configure do \|config\|
	# Use color in STDOUT
	config.color_enabled = true

	# Use color not only in STDOUT but also in pagers and files
	config.tty = true

	# Use the specified formatter
	config.formatter = :progress # :progress, :html, :textmate
	end

	describe Integer, '#to_roman' do

	it 'converts 1' do
	1.to_roman.should eq 'I'
	end

	it 'converts 2' do
	2.to_roman.should eq 'II'
	end

	it 'converts 3' do
	3.to_roman.should eq 'III'
	end

	it 'converts 4' do
	4.to_roman.should eq 'IV'
	end

	it 'converts 5' do
	5.to_roman.should eq 'V'
	end

	it 'converts 6' do
	6.to_roman.should eq 'VI'
	end

	it 'converts 9' do
	9.to_roman.should eq 'IX'
	end


	it 'converts 27' do
	27.to_roman.should eq 'XXVII'
	end

	it 'converts 48' do
	48.to_roman.should eq 'XLVIII'
	end

	it 'converts 59' do
	59.to_roman.should eq 'LIX'
	end

	it 'converts 93' do
	93.to_roman.should eq 'XCIII'
	end

	it 'converts 141' do
	141.to_roman.should eq 'CXLI'
	end

	it 'converts 163' do
	163.to_roman.should eq 'CLXIII'
	end

	it 'converts 402' do
	402.to_roman.should eq 'CDII'
	end

	it 'converts 575' do
	575.to_roman.should eq 'DLXXV'
	end

	it 'converts 911' do
	911.to_roman.should eq 'CMXI'
	end

	it 'converts 1024' do
	1024.to_roman.should eq 'MXXIV'
	end

	it 'converts 3000' do
	3000.to_roman.should eq 'MMM'
	end

	end
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