Abstraction in object-oriented programming

Inheritance and polymorphism in object-oriented programming

Encapsulation in object-oriented programming

Profile code to identify issues

Job preparation: Junior Programmer

Quiz: Apply object-oriented principles

Submission: Programming theory in action

Deep-dive into the pillars of object-oriented programming and their application, then learn how to profile and optimize code.

In this mission, you’ll refactor the inventory project you completed in the previous mission using the pillars of object-oriented programming as a guide. You’ll deep dive into the inner workings of each pillar individually, so you can better understand its value in developing applications. Next, you’ll learn how to profile your code to identify any optimization bottlenecks that would slow down the final build of your application. To close out this mission, you’ll develop a small application for your portfolio that uses fully optimized code built on OOP principles. 

When you complete this mission you will complete the Junior Programmer pathway - CONGRATULATIONS!

Apply Object-Oriented Principles

Unity Junior Programmer

Kickstart your programming career with Unity's Junior Programmer Pathway. Learn coding fundamentals, C#, and game development to create your first interactive projects. Start learning for free!

Junior Programmer Pathway - Learn Coding & Game Development | Unity Learn

We recommend that you have basic knowledge of Unity or complete 

Ready to code? This guided learning Pathway will take you from zero to job-ready!

Welcome to Junior Programmer! Designed for anyone interested in learning to code or obtaining an entry-level Unity role, this pathway assumes a basic knowledge of Unity and has no math prerequisites. Junior Programmer prepares you to get Unity Certified so that you can demonstrate your job-readiness to employers.

Junior Programmer

Course Introduction

Install Unity Software

Unit 1 - Introduction

Lesson 1.1 - Start your 3D Engines 

Lesson 1.2 - Pedal to the Metal

Lesson 1.3 - High Speed Chase

Lesson 1.4 - Step into the Driver's Seat

Challenge 1 - Plane Programming

Lab 1 - Project Design Document

Introduction to project management and teamwork

Quiz 1

Learn how to create new C# scripts, call basic functions, and use variables to modify the results of those functions.

In this first mission in the Junior Programmer pathway, you will program a car moving side-to-side on a floating road, trying to avoid (or hit) obstacles in the way. In addition to becoming familiar with the Unity editor and workflow, you will learn how to create new C# scripts and do some simple programming. By the end of the Unit, you will be able to call basic functions, then declare and tweak new variables to modify the results of those functions.

Player Control

Unit 2 - Introduction

Lesson 2.1 - Player Positioning

Lesson 2.2 - Food Flight

Lesson 2.3 - Random Animal Stampede

Lesson 2.4 - Collision Decisions

Challenge 2 - Play Fetch

Lab 2 - New Project with Primitives

Quiz 2

Mod the Cube

Quiz: Create with Code 1

Gain familiarity with some of the most important programming and Unity concepts, including if-then statements, random value generation, arrays, collision detection, prefabs, and instantiation.

In this Mission, you will program a top-down game with the objective of throwing food to hungry animals - who are stampeding towards you - before they can run past you. In order to do this, you will become much more familiar with some of the most important programming and Unity concepts, including if-then statements, random value generation, arrays, collision detection, prefabs, and instantiation. In completing this Unit, you will learn how to program a basic game with the ability to launch projectiles and maneuver the player to keep the game alive.

Basic Gameplay

Unit 3 - Introduction

Lesson 3.1 - Jump Force

Lesson 3.2 - Make the World Whiz By

Lesson 3.3 - Don't Just Stand There

Lesson 3.4 - Particles and Sound Effects

Challenge 3 - Balloons, Bombs, & Booleans

Lab 3 - Player Control

Quiz 3

Learn how to add music, sound effects, and visual particle effects to transform the experience of your project.

In this Mission, you will program a fast-paced endless side-scrolling runner game where the player needs to time jumps over oncoming obstacles to avoid crashing. In creating this prototype, you will learn how to add music and sound effects, completely transforming the experience of your projects. You will also learn how to create dynamic endless repeating backgrounds, which are critical for any side-scrolling games. Finally, you will learn to incorporate particle effects like splatters and explosions, which make your games so much more satisfying to play.

Sound and Effects

Unit 4 - Introduction

Lesson 4.1 - Watch Where You’re Going

Lesson 4.2 - Follow the Player

Lesson 4.3 - PowerUp and CountDown

Lesson 4.4 - For-Loops For Waves

Challenge 4 - Soccer Scripting

Lab 4 - Basic Gameplay

Quiz 4

Learn how to implement new gameplay mechanics including powerups and increasing difficulty.

In this Mission, you will program an arcade-style Sumo battle with the objective of knocking increasingly difficult waves of enemies off of a floating island, using power ups to help defeat them. In creating this prototype, you will learn how to implement new gameplay mechanics into your projects, which are new rules or systems that make the game more interesting to play. On one hand, you will learn to program a powerup, which give the player a temporary advantage. On the other hand, you will learn to program increasingly difficult enemy waves, which make survival more challenging for the player. A good balance of powerups and increasing difficulty make for a much more interesting gameplay experience.

Gameplay Mechanics

Unit 5 - Introduction

Lesson 5.1 - Clicky Mouse

Lesson 5.2 - Keeping Score

Lesson 5.3 - Game Over

Lesson 5.4 - What’s the Difficulty?

Challenge 5 - Whack-a-Food

Lab 5 - Swap out your Assets

Quiz 5

Introduction to user feedback and testing

Learn how to implement a User Interface - or UI - into your projects, such as a title screen and score display.

In this Mission, you will program a game to test the player’s reflexes, where the goal is to click and destroy objects randomly tossed in the air before they can fall off the screen. In creating this prototype, you will learn how to implement a User Interface - or UI - into your projects. You will add a title screen with a difficulty select menu that will control how challenging the gameplay is, you will add a score display that will track how many points the player has earned, and you will add a Game Over screen, which will allow the player to restart and try again. In learning these skills, you will be able to create a fully “playable” experience that the user can enjoy from start to finish without having to restart the application to try it again.

User Interface

Next Steps - Introduction

Lesson 6.1 - Project Optimization

Lesson 6.2 - Research and Troubleshooting

Lesson 6.3 - Sharing your Projects

ECS Survival Guide

Career research and preparation

Introduction to portfolios

Debug the App

Counting Prototype

Quiz: Create with Code 2

Prepare to continue developing your Unity and C# skills independently, including learning how to complete your personal project.

In this Mission, you'll prepare to continue developing your Unity and C# skills independently, including learning how to complete your personal project and how to prepare for the Unity Certified User: Programming exam, which you can take through your school program, if available.

Publishing Your Project

Introduction to real-time 3D experience design

Set up version control

Explore the sample project

Principles of object-oriented programming

Create a scene flow

Implement data persistence between scenes

Implement data persistence between sessions

Quiz: Manage scene flow and data

Submission: Data persistence in a new repo

Learn about data persistence and an introduction to the core pillars of object-oriented programming.

In this mission, you’ll learn about data persistence, or how to manage the loading and unloading of data between both scenes and sessions. Along the way, you will be introduced to the core pillars of object-oriented programming, which will help you structure your code throughout the mission. There will only be one practical example throughout the mission, which will build on the new functionality you create with each tutorial. At the end of this mission, you’ll take everything you learned and apply it to a new project by building a persistent score system for a small game.

Manage Scene Flow and Data

b74d745b-ba05-4a95-94cc-79dcf82c4b1d:626840369d40

Understand high-level programming concepts (such as inheritance, encapsulation, data abstraction, and polymorphism) and how they are implemented. 

Level 2 Programming theory

Joy Horvath

Instructional Designer

Use best practices and Unity's Profiler window to improve performance in code.

Level 1 Code optimization

This quiz will assess your understanding of the concepts covered in the  Junior Programmer: Apply object-oriented principles mission.

Explain how abstraction is used to expose only necessary script components

Explain how inheritance is used to share functionality between a parent and child class

Define the relationship between a parent and child class, including what a child class can and cannot do with respect to its parent class

Recognize opportunities where inheritance could be used to simplify code

Describe how polymorphism can be applied at compile time (method overloads) and run time (method overrides)

Explain how polymorphism is used to modify parent class functionality in a child class

Explain how encapsulation is used to write code that can only be used as intended by the programmer

Recommend a high-level system architecture for a given project 

Simplify code and make it reusable by correctly implementing the principles of inheritance and polymorphism

Expose only the important details of an object by correctly recognizing opportunities to implement abstraction

Control access to data within a class by applying encapsulation with getters and setters

Explain the purpose of interfaces, including their functional usability advantages over standard classes  

Make code more secure and usable by correctly implementing the principles of abstraction and encapsulation, including the use of interfaces

Identify potential simplification opportunities in code, such as splitting methods and reusing variables

Identify unnecessary nested if statements

Differentiate between public variables (properties), private variables (fields), and local variables

Store and organize data by applying data structures such as lists and dictionaries

Maximize code efficiency by correctly executing coding best practices

Enable easier readability and debugging by correctly organizing classes to include only singular purpose code

Add new functionality to non-editable classes by applying extension methods

Organize and prevent conflicts between scripts by using namespaces

Manage the communication of a GameObject’s status changes to other objects in the application by using Events 

Write efficient, organized, and comprehensible code by correctly implementing the principles of object-oriented programming

Deduce the script method that uses the most CPU time (vs. a script method that does not) by using the CPU profiler in the Profiler window 

Differentiate a loop that efficiently goes through a collection once in an Update() call from many loops that go through the same collection in an Update() call 

Recognize possible issues that might cause performance problems (e.g., too many RigidBody components, too many Colliders, too many shadows, etc.), given a scenario 

Investigate performance issues caused by poly count, texture sizes, or too many objects on the screen by using Unity's Stats window 

Deduce the script method that uses the most CPU time (vs. a script method that does not) by using the CPU profiler in the Profiler window

Differentiate a loop that efficiently goes through a collection once in an Update() call from many loops that go through the same collection in an Update() call

Recognize possible issues that might cause performance problems (e.g., too many RigidBody components, too many Colliders, too many shadows, etc.), given a scenario

Investigate performance issues caused by poly count, texture sizes, or too many objects on the screen by using Unity's Stats window

Debug performance issues

Analyze the principal pillars of object-oriented programming

In general, classes should be organized and written such that each class has a singular purpose.

True or False: In general, classes should be organized and written such that each class has a singular purpose.  

Organizing your classes to ensure they are written to include only singular purpose code makes for easier readability and debugging.

Why might you want to use an extension method in C#?

In order to extend the access of an existing method so it can be accessed from other classes.

In order to extend the functionality of an existing method using the same method name.

In order to add more parameters to an existing method.

In order to add functionality to an existing type without creating a new derived type. 

Extension methods effectively allow you to add methods to existing classes that could otherwise not be edited directly. This means that those classes do not need to be recompiled either.

 Which of the following statements are true about parent (base) and child (derived) classes?

A class can only inherit from a single class. 

Protected variables and methods can be accessed from the child class, even if they are separate scripts. 

Private variables and methods can be accessed from the child class, even if they are separate scripts. 

If Class C derives from Class B, which derives from Class A, Class C only inherits behaviors from Class B. 

 Which of the following statements are true about parent (base) and child (derived) classes? A class can only inherit from a single class.  Protected variables and methods can be accessed from the child class, even if they are separate scripts.  Private variables and methods can be accessed from the child class, even if they are separate scripts.  If Class C derives from Class B, which derives from Class A, Class C only inherits behaviors from Class B.   

For number 3, private variables and methods can only be accessed by derived classes if those classes are nested in their base class. For number 4, Class C would actually inherit from all base classes, which would include Class B and Class A.

If you were programming an application that allowed users to configure their own vehicles, how would you use the concept of inheritance to structure the code in a way that minimized redundancies?

Create a “Car” event, and have all vehicle types inherit from that event.

Create a base “Car” class, then create derived classes for different types of cars. 

Create a namespace called “Cars” and put all vehicle types in that namespace.

Create a method called “InheritCarBehavior”, which pulls in the functionality for a car.

Inheritance allows you to create child (derived) classes that inherit all behaviors from their parent (base) classes.

A base class (Class A) includes the following code:

public virtual void Greet () 
{
   Debug.Log("Hello");
}

A derived class (Class B) that derives from Class A includes the following code:

public override void Greet ()
{
   Debug.Log("How are you?");
}

If only Class B is instantiated and the Greet() method is called, what will appear in the console? 

A base class (Class A) includes the following code: public virtual void Greet () 
{
   Debug.Log("Hello");
} A derived class (Class B) that derives from Class A includes the following code: public override void Greet ()
{
   Debug.Log("How are you?");
} If only Class B is instantiated and the Greet() method is called, what will appear in the console?   

When an override method is called from a derived class, it completely overrides the parent method. If you also want to inherit the behavior from the parent class, you would need to add a line of code to call that method specifically with: base.Greet();

Which of the following practices are in support of the principle of “encapsulation” in C#?

Using public variables only when necessary

Deactivating objects in a scene that are not in use whenever possible. 

Using events that communicate only to abstract classes.

Which of the following practices are in support of the principle of “encapsulation” in C#? Using getters and setters  Using public variables only when necessary Deactivating objects in a scene that are not in use whenever possible.  Using events that communicate only to abstract classes.  

A major theme of encapsulation is safety in code — in other words, the process of ensuring that code is only used as it is intended to be used, and the values and data you are manipulating can’t be corrupted. In encapsulated code, other programmers can’t easily change the values of variables or the properties of objects. Getters and setters help with this, and so does limiting the number of public variables.

How would you replace the public variable below with a Property, which has improved security and still can be accessed from other classes.


How would you replace the public variable below with a Property, which has improved security and still can be accessed from other classes.
 public int score;    

A property can give access to a private field with the ability to get and set it.

How would you recommend improving the following code in order to improve its reusability?


void DisplayInfo(string name1, string name2, string address1, string address2, string phone1, string phone2)
{
     print(name1);
     print(name2);
     
     print(address1);
     print(address2);
     
     print(phone1);
     print(phone1);

}

How would you recommend improving the following code in order to improve its reusability?
 void DisplayInfo(string name1, string name2, string address1, string address2, string phone1, string phone2)
{
     print(name1);
     print(name2);
     
     print(address1);
     print(address2);
     
     print(phone1);
     print(phone1);

}    

Have DisplayInfo return an array composed of all of the strings.

Use literal strings instead of variables within the print method calls.

Shorten the variable names to n1, n2, a1, a2, p1, and p2

Create new methods for DisplayNames, DisplayAddresses, and DisplayPhoneNumbers, then call each of those methods from DisplayInfo(). 

In general, it is good practice to simplify code by extracting methods that are long or complex into separate methods, then to call those methods from within that method.

 The following is an example of code logic that is very difficult to understand:

public float GetValue()
{
     float result;      
     
     if (bool1)
     {
          result = 1;
      }
      else
      {
         if (bool2)
         {
            result = 2;
         }
         else
         {
            result = 0;
         }
     }
     return result;
 }

True or False: the code below would achieve the same result in a simpler way.

public float GetValue() {
     if (bool1)
     {
         return 1;
     }
     if (bool2)
     {
         return 2;
     }
     return 0; 
}

 The following is an example of code logic that is very difficult to understand: public float GetValue()
{
     float result;      
     
     if (bool1)
     {
          result = 1;
      }
      else
      {
         if (bool2)
         {
            result = 2;
         }
         else
         {
            result = 0;
         }
     }
     return result;
 } True or False: the code below would achieve the same result in a simpler way. public float GetValue() {
     if (bool1)
     {
         return 1;
     }
     if (bool2)
     {
         return 2;
     }
     return 0; 
}    

Quiz: Apply object-oriented principles

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