def caesar_encode(plaintext, shift)
	uppercase = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
	lowercase = "abcdefghijklmnopqrstuvwxyz"

	cipher = ""
	for char in plaintext
		if char in uppercase
			cipher += uppercase[uppercase[char] - (26 - shift)]
		else if char in lowercase
			cipher += lowercase[lowercase[char] - (26 - shift)]
		else
			cipher += char
		end
	end

	return cipher
end

def caesar_decode(cipher, shift)
	uppercase = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
	lowercase = "abcdefghijklmnopqrstuvwxyz"

	plaintext = ""
	for char in cipher
		if char in uppercase
			plaintext += uppercase[uppercase[char] - shift]
		else if char in lowercase
			plaintext += lowercase[lowercase[char] - shift]
		else
			plaintext += char
		end
	end

	return plaintext
end