Object Oriented Programming Basics

Study Notes

Object Oriented Programming Basics

Abstraction

Definition: Simplifying complex systems by modeling classes based on essential properties and behaviors while hiding unnecessary details.
Purpose: Helps in reducing programming complexity and increasing efficiency.
Implementation: Achieved using abstract classes and interfaces.
- Abstract Classes: Cannot be instantiated and may contain abstract methods (no implementation).
- Interfaces: Define a contract for classes to implement without providing common behavior.
Example: A 'Vehicle' class may encapsulate general properties like 'speed' and 'capacity,' while specific vehicle types (e.g., 'Car', 'Bike') implement unique behaviors.

Encapsulation

Definition: The bundling of data (attributes) and methods (functions) that operate on the data within a single unit or class.
Purpose: Protects object integrity by restricting direct access to some of the object's components.
Key Concepts:
- Access Modifiers: Control visibility and access to class members.
  - Private: Members accessible only within the same class.
  - Protected: Members accessible within the class and by derived classes.
  - Public: Members accessible from anywhere.
Example: A 'BankAccount' class may have private attributes like 'balance', and provide public methods like 'deposit()' and 'withdraw()' to manipulate it safely.

Polymorphism

Definition: The ability of different classes to be treated as instances of the same class through a common interface.
Types:
- Compile-time Polymorphism (Method Overloading): Same method name with different parameters within the same class.
- Run-time Polymorphism (Method Overriding): A subclass provides a specific implementation of a method already defined in its superclass.
Purpose: Enhances flexibility and reusability in code.
Example: A method draw() may be defined in a base class 'Shape', and overridden in derived classes like 'Circle' and 'Square' to provide specific drawing behavior.

Abstraction

Simplifies complex systems by modeling classes with essential properties and behaviors while concealing unnecessary details.
Reduces programming complexity and enhances efficiency by hiding irrelevant implementation details.
Achieved through abstract classes (which cannot be instantiated) and interfaces (which define contracts for classes without common behavior).
An abstract class may contain abstract methods that lack implementation, emphasizing the need for derived classes to provide specific functionality.
An example is the 'Vehicle' class, which encapsulates general attributes like 'speed' and 'capacity,' while subclasses like 'Car' and 'Bike' define their unique behaviors.

Encapsulation

Refers to bundling data (attributes) and methods (functions) that operate on this data into a single unit or class.
Protects the integrity of objects by restricting direct access to certain components, ensuring that data is manipulated only through defined methods.
Utilizes access modifiers to control the visibility of class members:
- Private: Accessible only within the same class.
- Protected: Accessible within the class and its derived classes.
- Public: Accessible from anywhere.
For instance, in a 'BankAccount' class, 'balance' can be a private attribute, while public methods 'deposit()' and 'withdraw()' allow for safe manipulation of the account balance.

Polymorphism

Denotes the ability to treat instances of different classes as instances of the same class via a common interface, promoting flexibility in code design.
Consists of two types:
- Compile-time Polymorphism: Achieved through method overloading, where multiple methods in a class share the same name but differ in parameters.
- Run-time Polymorphism: Achieved through method overriding, allowing a subclass to provide a specific implementation for a method defined in its superclass.
Enhances code reusability and flexibility, making it easier to extend and maintain systems.
An example of this is a draw() method defined in a 'Shape' base class, which is overridden in derived classes like 'Circle' and 'Square' to implement specific drawing behavior.

Description

This quiz covers the fundamental concepts of Object Oriented Programming, focusing on key principles such as Abstraction and Encapsulation. Students will learn how these principles help simplify complex systems and protect data integrity within software design. Test your understanding of abstract classes, interfaces, and the importance of encapsulation.