ROT13

rot13

rot13是凯撒的一种变种，仅仅只需要检查字母顺序并取代它在13位之后的对应字母

python实现

# -*-coding:utf-8-*-

def rot13_decode(s):
    res=""
    for i in s:
        if ord(i)>=ord('a') and ord(i)<=ord('z'):
            i = chr(ord(i)+13)
            if ord(i)>ord('z'):
                i = chr(ord(i)-26)

        if ord(i)>=ord('A') and ord(i)<=ord('Z'):
            i = chr(ord(i)+13)
            if ord(i)>ord('Z'):
                i = chr(ord(i)-26)

        res+=i
    return res

if __name__ == '__main__':
    str = raw_input("请输入字符串:")
    flag = rot13_decode(str)
    print flag

运行结果：