Teach your kids to code. Feature Learning to code. LINKS The Greenfoot Project

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Feature Learning to code Teach your kids to code WE TEAM UP WITH UNIVERSITY OF KENT TO INTRODUCE BRITAIN S CHILDREN TO THE BASICS OF COMPUTER PROGRAMMING O ne of the great ironies of having a

1 Feature Learning to code Teach your kids to code WE TEAM UP WITH UNIVERSITY OF KENT TO INTRODUCE BRITAIN S CHILDREN TO THE BASICS OF COMPUTER PROGRAMMING O ne of the great ironies of having a computer in every classroom is that not a single child in the class will know how to control it. Sure, they can turn it on, type a document, maybe even defrag the hard disk or tinker with the Control Panel, but how many could actually write a simple piece of code to make the PC do what they want, instead of what Microsoft does? Computer programming has largely slipped off the curriculum in our schools and, although the industry, universities and PC Pro would love it to make a comeback, there s little sign it will. So, in an attempt to bring the sought-after skills and self-satisfaction of programming a computer to a new generation, PC Pro has teamed up with the computing lab at the University of Kent to help parents teach their kids to code. LINKS The Greenfoot Project We ve created a 12-step tutorial to help parents sit down with their children at a computer and actually learn how to write the code that can manipulate a basic Java-based computer game. Over the next few months, we ll produce further tutorials covering topics such as basic website design, in an attempt to reignite enthusiasm for Britain s forgotten art of programming. And with PC Pro s computing enthusiast parents working alongside their children, it will provide an opportunity for mums and dads to pass on the skills they ve inherited over the years to their family. Nurturing tomorrow s techies Why is it vital that we breed a new generation of programmers? Take one look at the statistics. According to a joint report from Microsoft, the British Computer Society and Lancaster University Management School, more than 150,000 new computing graduates are needed every year to fill programming positions vacated by experienced software developers. Yet, universities report that applications for computing degrees are at an all-time 128 PC PRO FEBRUARY Kids & Code b (160).indd /11/07 16:38:35

WALKTHROUGH Design your own game 1 Go to www.greenfoot.org to download and install Greenfoot. Note that you must have the Java system installed on your PC to run the software.

2 The tutorial scenario is called Wombats. On the right-hand side, you ll see some Animal classes. Right-click on the Wombat class and select New Wombat().

*; public class Crab extends Animal 3 Download the Crabs scenario from www.greenfoot.org/scenarios/fi les/crab.zip and unzip it with WinZip.

Nothing will happen; we now need to program the crab to move. 4 Open the crab s editor by right-clicking on the crab actor class and selecting Open editor.

Then click Run and play with the Speed slider to control the crab s movement. public class Crab extends Animal turn(5); 5 Now we need to make the crab turn.

2 WALKTHROUGH Design your own game 1 Go to to download and install Greenfoot. Note that you must have the Java system installed on your PC to run the software. There s a link on Greenfoot s download page to get a Java system. When you open Greenfoot for the first time, select Open Tutorial and Tutorial Scenario for a brief introduction. 2 The tutorial scenario is called Wombats. On the right-hand side, you ll see some Animal classes. Right-click on the Wombat class and select New Wombat(). Drag the wombat into the world (the brown area of the main window). Now click on Act to make it move. The onscreen tutorial explains further interaction with objects. import greenfoot.*; public class Crab extends Animal 3 Download the Crabs scenario from les/crab.zip and unzip it with WinZip. Click on Scenario Open and select the Crabs folder you ve unzipped. Create a crab in the same way we created a wombat, place it in the world, and click run. Nothing will happen; we now need to program the crab to move. 4 Open the crab s editor by right-clicking on the crab actor class and selecting Open editor. In the box, Enter the command between the two symbols (as shown), close the editor and click Compile All. Place a crab in the world and click Act. Then click Run and play with the Speed slider to control the crab s movement. public class Crab extends Animal turn(5); 5 Now we need to make the crab turn. Open the crab s editor once more and include the turn command shown above. Note the figure in the brackets after the turn command tells the crab how many degrees to turn (five, in our example). Close the editor, press Compile All and try placing multiple crabs in the world to try it out. 6 The Move and Turn methods come from the Animal class. You can find out what other methods are available to use by opening the editor of the Animal class (rightclick on Animal and select Open Editor), and then switching to Documentation view from the drop-down menu. FEBRUARY 2008 PC PRO 129 Kids & Code b (160).indd /11/07 18:08:14

Feature Learning to code WALKTHROUGH Design your own game if (atworldedge()) turn(13); 7 In this list of methods, there s one called atworldedge() this makes the crab check if it s reached the edge

Remember once again to click Compile All, then place multiple crabs into the world and click Run to see what happens. 8 We now want to add a new animal.

Select that image and then click OK. You can then compile again and place the worm into the world. public void act () if (Greenfoot.isKeyDown( left )) turn(-7); if (Greenfoot.

class); 9 Next, we want to control the crab, so that we can catch worms. Every key on the keyboard has a name, for example left for the left cursor key.

10 Now, we want the crab to eat the worms when it comes across them. For this, we use the cansee and eat methods from the Animal class, as shown in the code above.

getrandomnumber(100) > 90) turn(greenfoot.getrandomnumber(90)-45); if (cansee(crab.class)) eat(crab.class); if (Greenfoot.isKeyDown( left )) turn(-7); if (Greenfoot.

3 Feature Learning to code WALKTHROUGH Design your own game if (atworldedge()) turn(13); 7 In this list of methods, there s one called atworldedge() this makes the crab check if it s reached the edge of the screen and turn. Using this method, we can modify our crab s code, as shown above. Remember once again to click Compile All, then place multiple crabs into the world and click Run to see what happens. 8 We now want to add a new animal. Right-click on the Animal class and select New Subclass. Type Worm as the class name make sure you use an upper-case W. You ll see there s a pre-prepared image of a sand worm. Select that image and then click OK. You can then compile again and place the worm into the world. public void act () if (Greenfoot.isKeyDown( left )) turn(-7); if (Greenfoot.isKeyDown( right )) turn(7); if (Greenfoot.isKeyDown( left )) turn(-7); if (Greenfoot.isKeyDown( right )) turn(7); if (cansee(worm.class)) eat(worm.class); 9 Next, we want to control the crab, so that we can catch worms. Every key on the keyboard has a name, for example left for the left cursor key. Delete the previous commands from the crab s editor and enter the text shown above. Now when you Compile All and Run you should be able to control the crab with the cursor keys. 10 Now, we want the crab to eat the worms when it comes across them. For this, we use the cansee and eat methods from the Animal class, as shown in the code above. Remember once again to use the upper-case W on Worm.class. Compile, place a crab and some worms into the world, and try it out. if(atworldedge()) turn(17); if(greenfoot.getrandomnumber(100) > 90) turn(greenfoot.getrandomnumber(90)-45); if (cansee(crab.class)) eat(crab.class); if (Greenfoot.isKeyDown( left )) turn(-7); if (Greenfoot.isKeyDown( right )) turn(7); if (cansee(worm.class)) eat(worm.class); Greenfoot.playSound( slurp.wav ); 11 To spice things up, we can add another creature. Let s add a lobster that runs around randomly and tries to eat the crab. Add the lobster as before, and write the code shown above into its editor. Recompile, then add a crab, three lobsters and a few worms, and see whether you can eat the worms before the lobsters catch you! 12 The final step is to add sound effects. In the crab class, at the place in the code where the crab eats the worm, place the command shown above to play a sound. Two sound files, named SLURP. WAV and AU. WAV, are provided. Similarly, add the AU.WAV sound in the Lobster s editor, where the lobster eats the crab. 130 PC PRO FEBRUARY 2008 Kids & Code b (160).indd /11/07 18:08:27

low. In a country that no longer has a manufacturing industry to speak of, we either take steps to address the growing skills gap in our computing industry or witness a vital part of the UK economy

4 low. In a country that no longer has a manufacturing industry to speak of, we either take steps to address the growing skills gap in our computing industry or witness a vital part of the UK economy wither. Worse still, universities report that the calibre of students arriving for computing-related degrees is woefully below par. Drop-out rates among firstyear students are higher than average, as students arrive without the necessary skills. But then that s hardly surprising when you consider that students can achieve an A* grade in GCSE Information Communications Technology (ICT) without writing a single line of code. As one student told PC Pro last year when we revealed the deplorable state of IT education in our schools (see web ID: 97391): Although I like using a PC, by the time I got to the end of the course I was getting bored. I suppose if I wanted to work as a computer programmer I d have carried on, but it doesn t interest me they re just there as a tool. Such indifference is hardly surprising given that the typical ICT GCSE syllabus includes modules on word processing, spreadsheets, health and safety, and the Data Protection Act, but never demands that children actually explore beyond the UI of applications and discover how software really works. It s like giving children a calculator but never explaining the underlying principles of multiplication. Teaching children office-automation skills borders on child abuse, says Dr Michael Kölling, the University of Kent academic, who s attempting to get the Greenfoot software we re using for our tutorial into schools across the country. There s a wide misconception that today s PCs are too complex for children to program The main problem for us is they call it computing. Kids think that s computer science. It isn t productive, it doesn t stimulate interest. Children should be creative, they should get the joy and satisfaction that comes from seeing their ideas take shape. What s even more galling is that, as computer use has exploded in both homes and offices, children s computing education has gone into reverse. Most IT professionals in their twenties or thirties probably have wistful memories of sitting in front of a BBC Micro at school and rattling out lines of Basic code. Many will also remember sitting in front of a Commodore 64 or ZX Spectrum at home and copying out basic programs from magazines or textbooks. None will have forgotten the satisfaction of seeing the program they d coded by hand come alive on the screen. Do today s children get that same sense of empowerment and discovery from tweaking a few tables in a Word document? What do you think? Impossibly complex? There s a wide misconception that today s PCs and software have grown so complex that it s impossible to teach children how to program them. Nonsense. The Java code used in the Greenfoot software we re using for our tutorial isn t significantly more complicated than the Basic of yesteryear. Greenfoot was launched in 2006, and is developed and maintained by staff at the University of Kent and Deakin University in Australia, with support from Sun Microsystems. It s since been used in schools and colleges across Europe and the US. Greenfoot provides a platform on which children as young as nine or ten can develop twodimensional simulations and simple games, while learning the valuable, object-orientated programming concepts that will serve them well in future computing courses and careers. Unlike those Basic programs of the mid-1980s, there s no need to painstakingly bash out lines of code to create basic graphics. Greenfoot includes a number of pre-prepared graphics fi les to allow children to control and manipulate the crabs, worms and lobsters found in the games, allowing them to focus on the mechanics of the software rather than the monotony of graphics coding. Greenfoot is a pure Java application that runs cross-platform on any modern Java VM. Since Greenfoot projects are themselves implemented on the standard Java platform, no limits exist to the sophistication and complexity that Greenfoot games may take, says its co-creator, Dr Kölling. The platform grows with the experience of the child, and even seasoned programmers can find interesting elements in this environment. The applications that users produce in Greenfoot can be exported to run as standalone applications or as applets running in standard web browsers. The tutorial we provide on p129 is only the beginning. Further tutorials, teaching materials and user communities can be found on the Greenfoot homepage at org if you want to help your child progress beyond the basics. And, if Dr Kölling s experience is anything to go by, children will be hungry to learn more. Teenage pupils can quite easily get to a level where they re making their own games within weeks, he claims. I ve done so with my daughter, who s eight. The tutorial is designed to be worked through with adult supervision. Some of the early steps, for example, require software installation that shouldn t be left to a child alone. Keep an eye out in PC Pro for the next instalment of our Teach Your Kids to Code series, and let us know how you get on with Greenfoot by dropping us an at letters@ pcpro.co.uk. FEBRUARY 2008 PC PRO 131 Kids & Code b (160).indd /11/07 18:21:50

Improving the Crab more sophisticated programming

CHAPTER 3 Improving the Crab more sophisticated programming topics: concepts: random behavior, keyboard control, sound dot notation, random numbers, defining methods, comments In the previous chapter,