Overview of OOPS Concept in Python

1. What is OOPS?

Object-Oriented Programming System (OOPS) is a programming method that organizes code using objects and classes. It helps in building clean, reusable, scalable, and maintainable applications.

2. Key OOPS Concepts

A. Class

A class is a blueprint/template for creating objects.

class Student:
    def __init__(self, name, marks):
        self.name = name
        self.marks = marks

B. Object

An object is an instance of a class.

s = Student("Sai", 90)

C. Encapsulation

Binding data (variables) and methods into a single unit (class). Also hides internal details.

class Bank:
    def __init__(self):
        self.__balance = 0  # private variable

    def deposit(self, amount):
        self.__balance += amount

D. Inheritance

One class acquiring properties/methods of another class.

class Animal:
    def sound(self):
        print("Some sound")

class Dog(Animal):
    def sound(self):
        print("Bark")

E. Polymorphism

Same method name behaving differently based on the object.

def make_sound(animal):
    animal.sound()

F. Abstraction

Hiding complex logic and showing only the necessary details. Achieved using abstract classes.

from abc import ABC, abstractmethod

class Car(ABC):
    @abstractmethod
    def start(self):
        pass

3. Why OOPS is Used in Real-Time Projects?

4. Real-Time Example – E‑Commerce Order System

This is how OOPS is applied in a real application:

class User:
    def __init__(self, name):
        self.name = name

class Order:
    def __init__(self, user, amount):
        self.user = user
        self.amount = amount

# Polymorphism Example
class Payment:
    def pay(self):
        pass

class UpiPayment(Payment):
    def pay(self):
        print("Paid using UPI")

class CardPayment(Payment):
    def pay(self):
        print("Paid using Card")

# Runtime Polymorphism
payment = UpiPayment()
payment.pay()

5. Summary of OOPS