def encrypt_text(input_text, key): encrypted_text = ""

for char in input_text:
    encrypted_char = chr(ord(char) + key)
    encrypted_text += encrypted_char

return encrypted_text

def decrypt_text(input_text, key): decrypted_text = ""

for char in input_text:
    decrypted_char = chr(ord(char) - key)
    decrypted_text += decrypted_char

return decrypted_text

input_text = "Hello, world!" key = 5

encrypted_text = encrypt_text(input_text, key) print("加密后的文本：", encrypted_text)

decrypted_text = decrypt_text(encrypted_text, key) print("解密后的文本：", decrypted_text)