roman_numeral.rb

def to_roman(num)
  results = ""

  if num % 5 == 4
    if num > 5
      results = "IX"
    else
      results = "IV"
    end
  elsif num == 5
    results = "V"
  elsif num == 10
    results = "X"
  else
    mod = num % 5
    if num > 5
      results = "V" + ("I" * mod)
    else
      results = "I" * mod
    end
  end

  results
end

# Driver code... this should print out trues.

puts to_roman(1) == "I"
puts to_roman(3) == "III"
puts to_roman(6) == "VI"

puts to_roman(9) == "IX"

# TODO: what other cases could you add to ensure your to_roman method is working?

puts to_roman(14) == "XIV"
puts to_roman(19) == "XIX"
puts to_roman(20) == "XX"

# write tests up to 9998