Introduction

Object-oriented programming (OOP) is a widely used programming paradigm based on the primary concept of objects, classes, attributes, and behaviors. OOP principles help model complex problems into various classes with related attributes and behaviors. It comprises a range of ideas that make code more readable, reusable, reliable, and maintainable.

This lesson will teach you about aggregation and composition while using a common theme of an e-commerce app throughout the module. Most people have purchased from a shop before or used an e-commerce app, making it easy to relate to the business use case in each scenario.

There are different ways to define the relationship between objects. You’ve already learned about inheritance in the “Introduction to Object-Oriented Programming in Kotlin” module. In this lesson, you’ll learn composition and aggregation using analogies, technical definitions, real-world use cases, and hands-on coding exercises to help you better understand and appreciate these principles.

By the end of this lesson, you’ll be able to:

• Distinguish between composition and aggregation in object-oriented programming.
• Create relationships between objects using composition and aggregation.
• Implement composition and aggregation in mobile development scenarios.