fractions.rb

# static constants
FRACTIONS_COUNT = 2
MIN_NUM = 1
MAX_NUM = 9999

# dynamic constants
CHAR_COUNT = MAX_NUM.to_s.length
FRACTION_DIVIDER = '-' * CHAR_COUNT

# helper function for getting user input
def get_user_input(value)
  puts "#{value}:"

  input = gets.chomp.to_i

  if input < MIN_NUM || input > MAX_NUM
    puts "You must enter a value between #{MIN_NUM} and #{MAX_NUM}."
    get_user_input(value)
  else
    input
  end
end

def pretty_s(numerator, denominator)
  "#{
    numerator.to_s.rjust(CHAR_COUNT)
  }\n#{
    FRACTION_DIVIDER
  }\n#{
    denominator.to_s.rjust(CHAR_COUNT)
  }"
end

class Fraction
  def initialize(numerator, denominator)
    @numerator = numerator
    @denominator = denominator
    @rational = Rational(numerator, denominator)
  end

  def to_s
    "#{@numerator}/#{@denominator}"
  end

  def to_pretty_s
    pretty_s(@numerator, @denominator)
  end

  def rational
    @rational
  end

  def numerator
    @rational.numerator
  end

  def denominator
    @rational.denominator
  end
end

class Fractions < Array
  def initialize(count)
    @fractions = []

    count.times { |i|
      no = i + 1

      puts "Enter #{no}# fraction:"

      @fractions << Fraction.new(
        get_user_input("numerator"),
        get_user_input("denominator")
      )

      puts @fractions[i].to_pretty_s
    }
  end

  def fractions
    @fractions
  end

  def rationals
    @fractions.map { |f| f.rational }
  end

  def sum
    result = rationals.reduce(:+)
    puts "\nResult:"
    pretty_s(result.numerator, result.denominator)
  end
end

fractions = Fractions.new(FRACTIONS_COUNT)
puts fractions.sum

puts fractions.fractions