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1. Create Class & Object2. Instance vs Class Variables3. Constructors in Python Classes4. Single Inheritance5. Multiple Inheritance6. Multilevel Inheritance7. Polymorphism with Methods8. Method Overloading Simulation9. Encapsulation with Getters/Setters10. Abstraction with ABC11. Operator Overloading12. Custom Iterator13. Class Methods14. Static Methods15. Composition Example16. Aggregation Example17. Private Variables18. Magic Methods Overview19. Object Cloning20. Custom Exceptions21. Class Decorator22. Prototype Pattern23. Singleton Pattern24. MRO (Method Resolution Order) Demo25. Polymorphism (Duck Typing)

Composition Example in Python

Use composition by placing one object inside another to build complex behavior.

IntermediateObject-Oriented ProgramsExample 15 of 25
composition-example.py
1# Program to demonstrate composition
2

3class Engine:
4    def start(self):
5        print("Engine started")
6

7class Car:
8    def __init__(self):
9        self.engine = Engine()
10

11    def drive(self):
12        self.engine.start()
13        print("Car is moving")
14

15c = Car()
16c.drive()

Output

Engine started
Car is moving

What's going on

Car is composed of an Engine object; it delegates the 'start' behavior to Engine instead of inheriting from it.

After this program

If the idea is still fuzzy, read Day 11: Classes and Objects in the Python course. For a short check, try the Python quiz (300 questions). Stay with all 25 object-oriented programs, or see every topic on Python exercises.

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