# File lib/quiz1/t/solutions/Jim Menard/solitaire_cypher.rb, line 184
def prep_arg(str)
    str = str.upcase.gsub(/[^A-Z]/, '')
    words = []
    while str.length > 0
        words << str[0...5]
        str[0...5] = ''
    end

    last_len = words[words.length-1].length
    words[words.length-1] += ('X' * (5 - last_len)) if last_len < 5
    words.join(' ')
end