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Resolved issue #12306

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Done for Hacktoberfest 2024
This commit is contained in:
Ayush Prem 2024-10-28 17:53:48 +05:30 committed by GitHub
parent 6e24935f88
commit 81d83abda9
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
1 changed files with 15 additions and 12 deletions
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27
ciphers/rot13.py
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@ -1,5 +1,7 @@
def dencrypt(s: str, n: int = 13) -> str:
def dencrypt(s: str) -> str:
"""
Performs ROT13 encryption/decryption on the input string `s`.
https://en.wikipedia.org/wiki/ROT13
>>> msg = "My secret bank account number is 173-52946 so don't tell anyone!!"
@ -9,29 +11,30 @@ def dencrypt(s: str, n: int = 13) -> str:
>>> dencrypt(s) == msg
True
"""
out = ""
# Validate input
assert isinstance(s, str), "Input must be a string"
# Using list to accumulate characters for efficiency
out = []
for c in s:
if "A" <= c <= "Z":
out += chr(ord("A") + (ord(c) - ord("A") + n) % 26)
out.append(chr(ord("A") + (ord(c) - ord("A") + 13) % 26))
elif "a" <= c <= "z":
out += chr(ord("a") + (ord(c) - ord("a") + n) % 26)
out.append(chr(ord("a") + (ord(c) - ord("a") + 13) % 26))
else:
out += c
return out
out.append(c)
return "".join(out)
def main() -> None:
s0 = input("Enter message: ")
s1 = dencrypt(s0, 13)
s1 = dencrypt(s0)
print("Encryption:", s1)
s2 = dencrypt(s1, 13)
print("Decryption: ", s2)
s2 = dencrypt(s1)
print("Decryption:", s2)
if __name__ == "__main__":
import doctest
doctest.testmod()
main()