include file.e

function rot13 (object o)
        if atom(o) then 
                o = {o}
        end if
        
        for i=1 to length (o) do
                if o[i] >= 'A' and o[i] <= 'Z' then
                        o[i] = remainder (o[i] - 'A' + 13, 26) + 'A'
                elsif o[i] >= 'a' and o[i] <= 'z' then
                        o[i] = remainder (o[i] - 'a' + 13, 26) + 'a'
                end if
        end for

        return o
end function

puts(1, "rot 13 encrypt/decrypt clu v.1\n")
puts(1, "----------------------------------------\n")
puts(1, "Please enter some text (CTRL-C to exit):\n")

object line
while not check_break () do
        line = gets(0)
        puts(1, '\n' & rot13(line))
        -- & is the string concatenation operator for euphoria
end while