🧠 Python OOP Mastery – 21 Core Assignments

Author: Muhammad Aryan
Date: May 19, 2025
Assignment Name: Python Object-Oriented Programming (OOP) – Core Principles & Applications
Objective: Grasp the essence of OOP in Python through 21 practical, real-world examples and concepts.

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📚 Assignment Index (21 Total)

1️⃣ Using self

Create a Student class with name and marks, initialized via self in the constructor. Includes display() method.

2️⃣ Using cls

Implement a Counter class with a class variable. Use @classmethod to track and display number of instances.

3️⃣ Public Variables and Methods

Build a Car class with a public variable brand and public method start(). Show how to access both from outside.

4️⃣ Class Variables & Class Methods

Create a Bank class with a class variable bank_name. Add change_bank_name() using @classmethod to update it.

5️⃣ Static Methods

Create MathUtils with a static method add(a, b) to return the sum of two numbers.

6️⃣ Constructors and Destructors

Design a Logger class that prints messages when an instance is created and destroyed.

7️⃣ Access Modifiers

In Employee, demonstrate:

• name (public)
• _salary (protected)
• __ssn (private, accessed via name mangling)

8️⃣ Using super()

Create a Person class with a constructor. Subclass Teacher uses super() to inherit and extend functionality with subject.

9️⃣ Abstract Classes

Use abc.ABC to create an abstract Shape class with area(). Implement it in Rectangle.

🔟 Class Method: Book Counter

Build a Book class with a class variable total_books. Use @classmethod to increment the count.

1️⃣1️⃣ Static Method: Temperature Conversion

Create TemperatureConverter with a static method to convert Celsius to Fahrenheit.

1️⃣2️⃣ Composition

Use Car and Engine classes to demonstrate composition—Engine object exists within Car.

1️⃣3️⃣ Aggregation

Use Department and Employee to model aggregation—a Department holds Employee references.

1️⃣4️⃣ Method Resolution Order (MRO)

Build a diamond inheritance structure: A, B, C, and D(B, C). Show method resolution using __mro__.

1️⃣5️⃣ Function Decorators

Write a function decorator log_function_call that announces when a function is being called.

1️⃣6️⃣ Class Decorators

Create a class decorator add_greeting that dynamically injects a greet() method into the class.

1️⃣7️⃣ @property, @setter, @deleter

Define a Product class with private _price and use property decorators to manage access and deletion.

1️⃣8️⃣ Callable Classes

Create a Multiplier class with a __call__() method, enabling objects to be used like functions.

1️⃣9️⃣ Custom Exceptions

Implement InvalidAgeError and raise it in check_age(age) if age < 18. Use try-except to handle it.

2️⃣0️⃣ Iterable Object: Countdown

Build a Countdown class that implements __iter__() and __next__() to count down from a start value to 0.

2️⃣1️⃣ Final Integration & Mastery

A review-worthy final structure demonstrating every aspect of OOP in an integrated and interconnected way. This includes:

• Clean object instantiation
• Property decorators
• MRO logic
• Decorators (function/class)
• Custom exceptions
• Composition and Aggregation

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⚙️ How to Run

1. Clone the repository:

git clone https://github.com/yourusername/python-oop-mastery.git
cd python-oop-mastery