module CousinRoman::Arabian

Public Instance Methods

build_pow(number, pow) click to toggle source
# File lib/cousin_roman/arabian.rb, line 34
def build_pow(number, pow)
  literals = CousinRoman.literals_for_pow pow

  case number
  when 1..3 then literals[:one]*number
  when 4 then literals[:subtractives][4]
  when 5..8 then literals[:five] + (literals[:one]*(number - 5))
  when 9 then literals[:subtractives][9]
  else ""
  end
end
build_roman(thousands, hundreds, tens, ones) click to toggle source
# File lib/cousin_roman/arabian.rb, line 27
def build_roman(thousands, hundreds, tens, ones)
  build_pow(thousands, 3) +
  build_pow(hundreds, 2) +
  build_pow(tens, 1) +
  build_pow(ones, 0)
end
convert(number) click to toggle source
# File lib/cousin_roman/arabian.rb, line 18
def convert(number)
  thousands = number / 1000
  hundreds = number / 100 % 10
  tens = number / 10 % 10
  ones = number % 10

  build_roman(thousands, hundreds, tens, ones).upcase
end
to_roman(arabian) click to toggle source
# File lib/cousin_roman/arabian.rb, line 9
def to_roman(arabian)
  convert arabian if valid? arabian
end
to_roman!(arabian) click to toggle source
# File lib/cousin_roman/arabian.rb, line 13
def to_roman!(arabian)
   valid? arabian or raise TypeError, 'not a valid roman number'
   convert arabian
end
valid?(number) click to toggle source
# File lib/cousin_roman/arabian.rb, line 5
def valid?(number)
  number.is_a? Integer and number >= 1 and number <= 3999
end