OOPs Class-3

Lecture 124:-  OOPs Class-3 

Let's continue our exploration of Object-Oriented Programming (OOP) with some more advanced concepts and examples.

1. Polymorphism and Method Overloading: Polymorphism allows objects of different classes to be treated as objects of a common superclass. Method overloading is a form of polymorphism where multiple methods in the same class have the same name but different parameters.

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class MathOperations: def add(self, a, b): return a + b def add(self, a, b, c): return a + b + c # Example usage math_ops = MathOperations() print(math_ops.add(2, 3)) # Throws an error, method overridden print(math_ops.add(2, 3, 4)) # Output: 9

2. Composition and Aggregation: Composition is a way to model a "has-a" relationship between classes, where one class contains another class as a part. Aggregation is a similar concept but with a weaker relationship.

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class Engine: def start(self): print("Engine started") class Car: def __init__(self): self.engine = Engine() def start(self): print("Car started") self.engine.start() # Example usage car = Car() car.start()

3. Singleton Pattern: The Singleton pattern ensures that a class has only one instance and provides a global point of access to that instance.

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class Singleton: _instance = None def __new__(cls): if cls._instance is None: cls._instance = super(Singleton, cls).__new__(cls) return cls._instance # Example usage instance1 = Singleton() instance2 = Singleton() print(instance1 == instance2) # Output: True

4. Factory Pattern: The Factory pattern provides an interface for creating objects in a super class, but allows subclasses to alter the type of objects that will be created.

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class Animal: def speak(self): pass class Dog(Animal): def speak(self): return "Woof!" class Cat(Animal): def speak(self): return "Meow!" class AnimalFactory: def create_animal(self, animal_type): if animal_type == "dog": return Dog() elif animal_type == "cat": return Cat() # Example usage factory = AnimalFactory() dog = factory.create_animal("dog") cat = factory.create_animal("cat") print(dog.speak()) # Output: "Woof!" print(cat.speak()) # Output: "Meow!"

These concepts provide you with more tools to design and implement flexible and maintainable software systems using object-oriented principles. Remember that OOP is a powerful paradigm that can greatly enhance your ability to model real-world entities and interactions in your programs.