readme

README.md

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+# Assignment 2 - Caesar Cipher
+
+This is my code for the OOP homework. I chose the Caesar Cipher Helper.
+
+- **Link:** https://www.codewars.com/kata/526d42b6526963598d0004db
+
+### How it works:
+- The `CaesarCipher` class takes a `shift` number.
+- `encode` changes text to uppercase and moves letters forward. It uses `% 26` so letters stay in the A-Z alphabet.
+- `decode` moves letters backward to fix the text.
+- Spaces and punctuation do not change.
+
+### Tools:
+I set up black and ruff with pre-commit hooks. They check and fix my code format before every commit.

src/oop_solution.py

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-class Animal:
+class CaesarCipher:
-    def __init__(self, name):
-        self.name = name
 
+    def __init__(self, shift: int):
+        self.shift = shift
+        self.alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 
-class Cat(Animal):
+    def encode(self, st: str) -> str:
-    def speak(self) -> str:
+        result = []
-        return f"{self.name} meows."
+        for char in st.upper():
+            if char in self.alphabet:
+                new_index = (self.alphabet.index(char) + self.shift) % 26
+                result.append(self.alphabet[new_index])
+            else:
+                result.append(char)
+        return "".join(result)
+
+    def decode(self, st: str) -> str:
+        result = []
+        for char in st.upper():
+            if char in self.alphabet:
+                new_index = (self.alphabet.index(char) - self.shift) % 26
+                result.append(self.alphabet[new_index])
+            else:
+                result.append(char)
+        return "".join(result)