Ruby中的Ceasars密码

def encrypt(text, shift)
  encrypted_text = ""
  text.each_char do |char|
    if char.match(/[A-Za-z]/)
      ascii_offset = char.match(/[A-Z]/) ? 65 : 97
      encrypted_char = ((char.ord - ascii_offset + shift) % 26 + ascii_offset).chr
      encrypted_text += encrypted_char
    else
      encrypted_text += char
    end
  end
  return encrypted_text
end

def decrypt(encrypted_text, shift)
  decrypted_text = ""
  encrypted_text.each_char do |char|
    if char.match(/[A-Za-z]/)
      ascii_offset = char.match(/[A-Z]/) ? 65 : 97
      decrypted_char = ((char.ord - ascii_offset - shift) % 26 + ascii_offset).chr
      decrypted_text += decrypted_char
    else
      decrypted_text += char
    end
  end
  return decrypted_text
end

# 示例用法
plaintext = "Hello, World!"
shift = 3

encrypted_text = encrypt(plaintext, shift)
puts "加密后的文本：#{encrypted_text}"

decrypted_text = decrypt(encrypted_text, shift)
puts "解密后的文本：#{decrypted_text}"