From 4879a46be1c056cceb46be12155796a75f070c68 Mon Sep 17 00:00:00 2001
From: Srivaishnavi Yaddanapudi
 <127314796+Y-Srivaishnavi@users.noreply.github.com>
Date: Tue, 29 Oct 2024 16:52:40 +0530
Subject: [PATCH 1/5] Fix number of rotations `N` as 13 (Resolves
 TheAlgorithms#12306)

---
 ciphers/rot13.py | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/ciphers/rot13.py b/ciphers/rot13.py
index b367c3215127..5deb87c5df2a 100644
--- a/ciphers/rot13.py
+++ b/ciphers/rot13.py
@@ -1,4 +1,4 @@
-def dencrypt(s: str, n: int = 13) -> str:
+def dencrypt(s: str) -> str:
     """
     https://en.wikipedia.org/wiki/ROT13
 
@@ -9,12 +9,13 @@ def dencrypt(s: str, n: int = 13) -> str:
     >>> dencrypt(s) == msg
     True
     """
+    N = 13
     out = ""
     for c in s:
         if "A" <= c <= "Z":
-            out += chr(ord("A") + (ord(c) - ord("A") + n) % 26)
+            out += chr(ord("A") + (ord(c) - ord("A") + N) % 26)
         elif "a" <= c <= "z":
-            out += chr(ord("a") + (ord(c) - ord("a") + n) % 26)
+            out += chr(ord("a") + (ord(c) - ord("a") + N) % 26)
         else:
             out += c
     return out

From 5efef35d8d481b40f450f65418e59741a479d22b Mon Sep 17 00:00:00 2001
From: Srivaishnavi Yaddanapudi
 <127314796+Y-Srivaishnavi@users.noreply.github.com>
Date: Tue, 29 Oct 2024 17:04:58 +0530
Subject: [PATCH 2/5] Add input validation and change function name to
 `apply_rot13`

---
 ciphers/rot13.py | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/ciphers/rot13.py b/ciphers/rot13.py
index 5deb87c5df2a..d7c2bace3ba6 100644
--- a/ciphers/rot13.py
+++ b/ciphers/rot13.py
@@ -1,14 +1,19 @@
-def dencrypt(s: str) -> str:
+def apply_rot13(s: str) -> str:
     """
-    https://en.wikipedia.org/wiki/ROT13
+    Performs a special case of the Caesar cipher.
+    Rotates the plaintext by 13 letters.
+    Also see: https://en.wikipedia.org/wiki/ROT13
 
+    Example usage:
     >>> msg = "My secret bank account number is 173-52946 so don't tell anyone!!"
-    >>> s = dencrypt(msg)
+    >>> s = apply_rot13(msg)
     >>> s
     "Zl frperg onax nppbhag ahzore vf 173-52946 fb qba'g gryy nalbar!!"
-    >>> dencrypt(s) == msg
+    >>> apply_rot13(s) == msg
     True
     """
+    if not isinstance(s, str):
+        return "The input must be a string. Please try again."
     N = 13
     out = ""
     for c in s:
@@ -24,10 +29,10 @@ def dencrypt(s: str) -> str:
 def main() -> None:
     s0 = input("Enter message: ")
 
-    s1 = dencrypt(s0, 13)
+    s1 = apply_rot13(s0)
     print("Encryption:", s1)
 
-    s2 = dencrypt(s1, 13)
+    s2 = apply_rot13(s1)
     print("Decryption: ", s2)
 
 

From 2bef9b9cb35e7f55aa3544f4fd7f2e467fac3a1c Mon Sep 17 00:00:00 2001
From: Srivaishnavi Yaddanapudi
 <127314796+Y-Srivaishnavi@users.noreply.github.com>
Date: Tue, 29 Oct 2024 17:06:56 +0530
Subject: [PATCH 3/5] Update documentation

---
 ciphers/rot13.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/ciphers/rot13.py b/ciphers/rot13.py
index d7c2bace3ba6..bd6b2ac89fd2 100644
--- a/ciphers/rot13.py
+++ b/ciphers/rot13.py
@@ -1,7 +1,7 @@
 def apply_rot13(s: str) -> str:
     """
-    Performs a special case of the Caesar cipher.
-    Rotates the plaintext by 13 letters.
+    Performs a special reversible case of the Caesar cipher.
+    Rotates a text by 13 letters.
     Also see: https://en.wikipedia.org/wiki/ROT13
 
     Example usage:

From 92d58b7109f529a0ba950acc5050a7d3d1fda4c2 Mon Sep 17 00:00:00 2001
From: Srivaishnavi Yaddanapudi
 <127314796+Y-Srivaishnavi@users.noreply.github.com>
Date: Tue, 29 Oct 2024 17:21:43 +0530
Subject: [PATCH 4/5] Add `.split

---
 ciphers/rot13.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/ciphers/rot13.py b/ciphers/rot13.py
index bd6b2ac89fd2..60a380ef3ccd 100644
--- a/ciphers/rot13.py
+++ b/ciphers/rot13.py
@@ -27,13 +27,13 @@ def apply_rot13(s: str) -> str:
 
 
 def main() -> None:
-    s0 = input("Enter message: ")
+    s0 = input("Enter message: ").strip()
 
     s1 = apply_rot13(s0)
     print("Encryption:", s1)
 
     s2 = apply_rot13(s1)
-    print("Decryption: ", s2)
+    print("Decryption:", s2)
 
 
 if __name__ == "__main__":

From 3a98cdab6e8298452368f689bb7d1ee5c0311d2e Mon Sep 17 00:00:00 2001
From: Srivaishnavi Yaddanapudi
 <127314796+Y-Srivaishnavi@users.noreply.github.com>
Date: Tue, 29 Oct 2024 17:34:37 +0530
Subject: [PATCH 5/5] Change `N` into lowercase

---
 ciphers/rot13.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/ciphers/rot13.py b/ciphers/rot13.py
index 60a380ef3ccd..9a04c05df5af 100644
--- a/ciphers/rot13.py
+++ b/ciphers/rot13.py
@@ -14,13 +14,13 @@ def apply_rot13(s: str) -> str:
     """
     if not isinstance(s, str):
         return "The input must be a string. Please try again."
-    N = 13
+    n = 13
     out = ""
     for c in s:
         if "A" <= c <= "Z":
-            out += chr(ord("A") + (ord(c) - ord("A") + N) % 26)
+            out += chr(ord("A") + (ord(c) - ord("A") + n) % 26)
         elif "a" <= c <= "z":
-            out += chr(ord("a") + (ord(c) - ord("a") + N) % 26)
+            out += chr(ord("a") + (ord(c) - ord("a") + n) % 26)
         else:
             out += c
     return out