Greenfoot

Course Structure Summary Component 1 – Understanding Computer Science (Theory) Written examination – 50% // 1 hour 45 Minutes Component 2 - Computational Thinking and Programming (Java&OO) On Screen Exam – 30% // 2 Hours (1 session) Component 3 – Software Development Non exam Assessment – 20% // 20 hours (multiple sessions)

Prior Knowledge checklist… In order to access this lesson you should be comfortable with… Basic Input and Output in Python Data types – INT, STR, BOOL, Double/Decimal/Real Performing Mathematical operation and storing the results(ie CircleArea = 3.14 * r * r) If statements (including ELSEIF and ELSE) FOR Loops and WHILE loops Functions

How does Component 2 work? You will have an “On Screen” exam next summer in year 11. This will be in a computer room and the exam will be run in the same way as a standard examination. All of you answers will be submitted on the computers and you will not have to write anything down on paper. There are three core skills that will be assessed on the exam…. Knowledge of HTML General coding skills (Python) Object Orientation & Java (Greenfoot) You will be provided with an exam paper which will list of all of the tasks that you must complete. A sample can be seen on the next few slides…

Are of focus… You have already been learning how to code using Python (V3). In these lessons we will focus on using GreenFoot and learning about Object orientation. This will leave HTML to learn in order for you to be able to access the exam.

Open the environment. Have a look at the Greenfoot enviroment and explore what type of applications you will be asked to adapt and built. NOTE: You will not be asked to build a game or application from scratch. The exam will always provide you with base files that you can then use to either adapt code or add additional code.

Explore and Discover The GreenFoot IDE Open Green Foot and open a game template. Explore the game and find the following…. 1. Find the Act button 2. find the Pause button 3. Find the Reset button 4. Find the Speed Slider 5. Find the World 6. Find the Classes for The world and the actor 7. View key information for base class World Actor 8. View the code for each class for each actor and world (likely only one world)

Modern Crab The speed of the code is controlled here Press “Act” to run the code one step at a time Press “Run” or “Pause” to start or pause the code Press “Reset” to reset to the start

You can view the code for each object by double clicking here

{ } Notice how the code is split into separate functions. These functions are grouped by using braces { } Each function has a name.. Public void act()

You cannot see the code for the base classes. For these you will only see an overview.

This documentation tell you how it works rather than showing you all of the code. Notice that all of the functions are still listed even through you cannot see the code.

Greenfoot – Installing Greenfoot You can download the Greenfoot IDE at home. It is simple to install

Finding pre-built Scenarios It is important that you get familiar with the GreenFoot IDE and that it can be used to create multiple different scenarios. Visit the Greenfoot website and download some games and look at the code that makes them work.

Beginning to understand what is going on… Now that you have an idea of how the IDE works it is important to start thinking about how the code works. We will be working through… Classes Vs Objects Findings the “initialising” function Inheritance (Extending)

Object orientations - Classes Note: This can often be tricky to understand at first. A class is a set of instructions that tell the computer how to built an object. Think of a Class as a recipe for a cake. You cannot eat the recipe. The recipe is not an actual cake. You follow the recipe to make a cake. So you either have… The object cake (an actual cake made from the recipe) The class cake (the recipe used to make a cake) So… the object cake is an instance of the class cake

Object orientation. Once you have created your classes you can create multiple instances of an object very quickly. This is very powerful, it allows you to create multiple objects whilst using very little code. For example Class Cake (recipe) Cake Objects (Actual Cakes)

Classes - GreenFoot In greenfoot you can find the objects on the right of the IDE. These are the recipes that will be used to make all of the objects that you can see.

Objects – GreenFoot You will notice that there are multiple instances of each class created.

Inheritance [To be covered in a future lesson]