def encrypt_string(string):
result = ""
for i, c in enumerate(string):
# 计算新的ascii码值
ascii_value = ord(c) + i
# 判断ascii码是否超出字母范围,是则减去26
if c.islower() and ascii_value > ord('z'):
ascii_value -= 26
elif c.isupper() and ascii_value > ord('Z'):
ascii_value -= 26
result += chr(ascii_value)
return result
a = input("输入字符串(只能是字母)")
b = encrypt_string(a)
print("加密后是 ", b)