Object Oriented Programming

Object (Definition)

A self-contained unit of code combining data and functionality in a single independent unit.

Object (Runtime & Real-world)

Exists in memory during runtime with own data; e.g., a specific car with its color.

Class

A blueprint or template used to create objects, defining variables and methods.

Encapsulation

Bundling attributes and methods in a class, controlling access using public and private.

Encapsulation (Purpose)

Protects variables from being changed by outside code.

Abstraction

Simplifying complex systems by hiding implementation details and exposing only what is necessary.

Abstraction Example

Driving a car using the accelerator without knowing how the engine accelerates.

Inheritance

When a subclass takes on variables and methods of a parent class.

Inheritance (Purpose & Example)

Ensures code reusability; e.g., SportsCar and Truck inheriting speed from a base Vehicle.

Generalisation

Identifying shared features across specific things and combining them into a reusable solution.

Generalisation Example

Grouping shared traits of lions and tigers into one generalized Animal class.

Polymorphism

Different classes using the exact same method name to perform completely different actions.

Polymorphism Example

A TakeScreenshot class and a MuteMicrophone class both executing their unique tasks via Execute().

Procedural programming

A step by step method that breaks down the program into reusable routines which are called subprograms or functions.

Object oriented programming

A programming paradigm organised around objects and their associated behaviours (methods) rather than sequential logic.

Procedural Programming - Linear Execution

The computer processes code sequentially from the first line down to the last line.

OOP - Blueprints

Classes act as the master blueprints that dictate how every object behaves and handles data.

Procedural Programming - Function Driven

Code is grouped into reusable blocks called procedures, routines, or functions.

Procedural Programming - Design Approach

Uses a top-down design, breaking one big task into smaller steps.

OOP - Object Creation

You can create one master blueprint (class) and instantly pump out hundreds of unique versions (objects).

Procedural Programming - Shared State

Programs rely heavily on global variables that any function can see and change.

OOP - Design Approach

Uses a bottom-up design, making individual pieces first and linking them.

Task definition

A clear explanation of an issue or challenge summing up what you want to change.

Top-down approach

Breaking a complex algorithm down into smaller units called modules.

Bottom-up approach (OOP)

Creating basic classes and objects first, then combining them into larger systems.

Facade pattern

Hides system complexities and provides a single, simplified interface to the client.

Abstraction vs. Facade Pattern

Abstraction hides details of one object; Facade provides a simplified interface to many subsystems.

Agility

The ability of a program to adapt to changing requirements without major changes.

Message-passing

A behaviour in OOP where objects communicate by sending data rather than accessing each other's code.

Message-passing example

Collision is triggered by the player when touched by the lava, it passes a function in the player's object to kill the player

Code optimisation

Modifying code so programs run faster and use less memory.

Python Optimisation: Built-in Functions

Use functions like sum() or max() which run on highly optimized, compiled C code.

Python Optimisation: Generators

Use parentheses () instead of brackets [] to process large datasets one item at a time.

Python Optimisation: String Concatenation

Use "".join(list) instead of looping with += to avoid recreating strings in memory.

Collaborative code development

When a team of programmers work together to build software.

Consistency

When the rules of the program stay the same throughout when writing the code.

Consistency (Formatting)

Standardizing parentheses and spacing so the code looks written by a single person.

Consistency (Naming Conventions)

Developers using intrinsic, meaningful names for their variables.

Consistency (Design Pattern)

Using a standard structure for the overall organization of the code.

Code commenting

Adding notes to sections of your code, explaining its meaning and intent.

Version control

A management system that allows access to a complete history of your process.

Feedback

The ongoing process of getting project feedback to fix mistakes immediately.

Clear and uncluttered mainline

Keeping the main starting section of code short and simple by using subroutines.

One logical task per subroutine

Designing each subroutine to perform only one job for readability and reusability.

Stub

A placeholder dummy code returning hardcoded data used during software testing.

Stub (Dependencies)

Eliminates dependencies, allowing testing before external systems or team code are finished.

Stub (Speed)

Increases speed by returning hardcoded data instantly instead of making slow network calls.

Stub (Predictability)

Guarantees reliable test results by always returning the exact same data.

Stub (Edge Cases)

Simulates rare scenarios like server crashes or network timeouts to test error handling.

Data Structures

Creating specific data formats like lists or dictionaries to process information.

Control Structures

Altering logic flow or data organization using loops or conditional statements.

Data & Control Structures Example

Netflix loading a show list (data structure) and looping to draw thumbnails (control structure).

Ease of maintenance

How easily software can be updated, repaired, and expanded over time.

Regular backup

An automated process of saving code copies to prevent work loss from bugs.

Unit Testing

Testing one small, individual piece of code in isolation to ensure it works correctly.

Subsystem Testing

Integration testing verifying the behavior and interaction between multiple components within a subsystem.

System Testing

Testing the entire completed application from start to finish to validate overall functionality.

White Box Testing

Testing technique requiring full knowledge of internal code to test syntax, logic, or runtime errors.

Black Box Testing

Testing technique where inputs and outputs are known, requiring no coding experience.

Grey Box Testing

Testing technique where the tester has partial knowledge of internal code, structures, or architecture.

Quality Assurance

Ongoing process of testing and checking software to ensure reliability and meet design requirements.

Alpha Testing

Testing performed by developers in a controlled environment to check for core functionality.

Beta Testing

Testing performed by real users in their own environment to gather feedback on reliability.