added caesar cipher

caesar.py

@@ -0,0 +1,39 @@
+def caesarEncrypt(text, shift):
+    result = []
+
+    for char in text:
+        # Check if the character is an uppercase letter
+        if 'A' <= char <= 'Z':
+            # Rotate the character by 13 within the uppercase letters
+            result.append(chr((ord(char) - ord('A') + shift) % 26 + ord('A')))
+
+        # Check if the character is a lowercase letter
+        elif 'a' <= char <= 'z':
+            # Rotate the character by 13 within the lowercase letters
+            result.append(chr((ord(char) - ord('a') + shift) % 26 + ord('a')))
+
+        else:
+            # If it's not a letter, keep it unchanged
+            result.append(char)
+
+    return ''.join(result)
+
+def caesarDecrypt(text, shift):
+    result = []
+
+    for char in text:
+        # Check if the character is an uppercase letter
+        if 'A' <= char <= 'Z':
+            # Rotate the character by 13 within the uppercase letters
+            result.append(chr((ord(char) - ord('A') - shift) % 26 + ord('A')))
+
+        # Check if the character is a lowercase letter
+        elif 'a' <= char <= 'z':
+            # Rotate the character by 13 within the lowercase letters
+            result.append(chr((ord(char) - ord('a') - shift) % 26 + ord('a')))
+
+        else:
+            # If it's not a letter, keep it unchanged
+            result.append(char)
+
+    return ''.join(result)

gitignore

@@ -0,0 +1,3 @@
+/__pycache__
+/__pycache__/*
+__pycache__/*

main.py

@@ -1,5 +1,6 @@
 import argparse
-from rot13 import rot13encrypt, rot13decrypt
+from rot13 import rot13Encrypt, rot13Decrypt
+from caesar import caesarEncrypt, caesarDecrypt
 
 # Create an ArgumentParser object
 parser = argparse.ArgumentParser(description="Process user text to encrypt or decrypt it using various algorithms.")
@@ -8,14 +9,22 @@
 parser.add_argument('-a', '--algorithm', type=str, required=True, help='Choose an algorithm (e.g. ROT13)')
 parser.add_argument('-d', '--decrypt', action='store_true', help='decrypt a text')
 parser.add_argument('-t', '--text', type=str, required=True, help='Text you want to encrypt/decrypt')
+parser.add_argument('-s', '--shift', type=int, help='Number of shifts a char should do (e.g. 7 a->h)')
 
 args = parser.parse_args()
 
-
 if args.algorithm == "rot13":
     if args.decrypt == True:
-        dec_string = rot13decrypt(args.text)
+        dec_string = rot13Decrypt(args.text)
+        print(f"encrypted: {args.text} -> decrypted: {dec_string}")
+    else:
+        enc_string = rot13Encrypt(args.text)
+        print(f"cleartext: {args.text} -> encrypted: {enc_string}")
+
+if args.algorithm == "caesar" and args.shift != None:
+    if args.decrypt == True:
+        dec_string = caesarDecrypt(args.text, args.shift)
         print(f"encrypted: {args.text} -> decrypted: {dec_string}")
     else:
-        enc_string = rot13encrypt(args.text)
-        print(f"cleartext: {args.text} -> encrypted: {enc_string}")
+        enc_string = caesarEncrypt(args.text, args.shift)
+        print(f"cleartext: {args.text} -> encrypted: {enc_string}")

rot13.py

@@ -1,6 +1,6 @@
 # ROT13 Implementation Script
 
-def rot13encrypt(text):
+def rot13Encrypt(text):
     result = []
 
     for char in text:
@@ -20,7 +20,7 @@ def rot13encrypt(text):
 
     return ''.join(result)
 
-def rot13decrypt(text):
+def rot13Decrypt(text):
     result = []
 
     for char in text: