OOP in Real Projects

একটা E-commerce System এ আমরা যদি OOP এপলাই করি, তাহলে 

Encapsulation 

Order hides its details but exposes methods like placeOrder().

Abstraction

Payment interface with implementations CreditCardPayment, PayPalPayment.

Inheritance:

AdminUser and CustomerUser extend User.

Polymorphism 

sendNotification() can be SMS, Email, or Push Notification.