Activity: Concept of OOP

Brief Intro — Concept of OOP

From spaghetti code to objects that think like the real world — the design philosophy behind modern programming. In this activity, we transition from sequential and procedural control flows to the structured domain of Object-Oriented Programming (OOP).

Task 1: Classification of Programming Paradigms

Programming paradigms can be classified into three distinct categories:

• Unstructured Programming: The most primitive paradigm, featuring a sequential flow of control where code is repeated throughout the program.
• Structured Programming: Features a non-sequential flow of control where the use of functions allows for code re-use.
• Object Oriented Programming: The most recent concept which combines data and actions together into individual units.

Task 2: Unstructured Banking Software Case Study

Consider designing a Banking Software with functions like Deposit, Withdraw, and ShowBalance. An unstructured implementation uses global variables and sequential lines directly:

int account_number = 20;
int account_balance = 100;

account_balance = account_balance + 100;
printf("Account Number = %d", account_number);
printf("Account Balance = %d", account_balance);

account_balance = account_balance - 50;
printf("Account Number = %d", account_number);
printf("Account Balance = %d", account_balance);

Why it hurts: For any further deposit or withdrawal operation, you must copy and repeat the exact same display and mathematical lines again and again, leading to redundant, fragile code.

Task 3: Objects and Message Passing

OOP is similar to the way the real world works and is analogous to the human brain. Every program is made up of entities called objects, which are the fundamental units having behavior or a specific purpose associated with them.

Crucially, objects cannot directly access another object's data. To complete computations, each object receives messages, processes data, and sends messages to other objects, interacting via their own methods and data.

Task 4: OOP vs Procedural Programming

Procedural programming focuses on writing procedures or functions that perform operations on data, whereas OOP is about creating objects that contain both data and functions together. OOP provides several clear advantages:

• OOP is faster and easier to execute.
• OOP provides a clear structure for programs.
• OOP keeps code DRY ("Don't Repeat Yourself"), making it easier to maintain, modify, and debug.
• OOP enables full reusable applications with less code and shorter development time.

Task 5: Class vs Object

A Class is a programmer-defined data type which includes local functions as well as local data. It serves as a template for making instances, forming a logical component rather than a physical entity. For example, a class "Expensive Cars" can define properties like price or speed, and methods like driving, reverse, and braking.

An Object is an individual instance of the data structure defined by a class. Objects are physical entities or instances created from that template, such as a specific Mercedes, BMW, chair, bike, marker, pen, table, or car.

Task 6: Inheritance

Inheritance is the concept where one object acquires the properties and behaviors of a parent object, establishing a robust parent-child relationship between two classes. It offers a natural mechanism for organizing and structuring software by letting child classes inherit member functions and variables from parent classes.

Task 7: Polymorphism

Polymorphism is the ability of a variable, object, or function to take on multiple forms. It allows the same function name to be used for different purposes by accepting different numbers of arguments or doing different tasks.

Analogy: In English, the verb "run" has entirely different meanings when applied to a laptop, a foot race, or a business. We deduce the correct form based on surrounding context, exactly how polymorphism functions in code.

Task 8: Encapsulation and Abstraction

Encapsulation: The act of wrapping data and code together to form an object. Class variables remain hidden from other classes and can only be accessed through methods of their current class. Analogy: In a school, a student cannot exist independently without a class.

Abstraction: The act of representing essential features without including background details. Analogy: While driving a car, you only concern yourself with the steering wheel, gears, and accelerator, rather than the intricate internal engineering of the engine.

Task 9: Constructors and Destructors

OOP introduces specialized lifetime management functions:

• Constructor: A special function called automatically whenever there is an object formation from a class.
• Destructor: A special function called automatically whenever an object is deleted or goes out of scope.

Task 10: Structured Solution

With structured programming, repeated lines are organized into reusable blocks called functions or methods. Instead of repeating lines, a simple call to ShowBalance() is made, isolating the display logic from individual calculations.

▶ Try it: Structured

Task 11: The Object-Oriented Cleanliness

OOP binds data fields (account_number, account_balance) and actions (ShowBalance()) together inside a unified Account class. An instance myAC is instantiated, preventing internal data manipulation from drifting freely across external code blocks and opening the door to Abstraction, Encapsulation, Inheritance, and Polymorphism.

▶ Try it: OOP

Task 12: Interactive Concept Categorization Map

Select a concept tag from the pool below, then click on the correct classification bucket to place it. Match all four items perfectly to verify your mapping.