What is Object-Oriented Programming (OOP) and what are its 4 pillars? Object-Oriented Programming (OOP) क्या है और इसके 4 pillars क्या हैं?

OOP is a programming paradigm based on objects and classes. The 4 pillars of OOP are: Encapsulation, Inheritance, Polymorphism, and Abstraction.

# Encapsulation - hiding internal details
class BankAccount:
    def __init__(self, balance):
        self.__balance = balance  # Private
    
    def deposit(self, amount):
        self.__balance += amount
    
    def get_balance(self):
        return self.__balance

# Inheritance - reusing code
class Animal:
    def speak(self):
        pass

class Dog(Animal):
    def speak(self):
        return 'Woof!'

# Polymorphism - same method, different behavior
dog = Dog()
cat = Cat()
print(dog.speak())  # Woof!
print(cat.speak())  # Meow!

# Abstraction - hide complexity
from abc import ABC, abstractmethod

class Shape(ABC):
    @abstractmethod
    def area(self):
        pass

class Circle(Shape):
    def __init__(self, radius):
        self.radius = radius
    
    def area(self):
        return 3.14 * self.radius ** 2