Category Archives: Joy Of Code

Joy of Code videos in German

Do you want to learn programming with Greenfoot? Do you speak German? Is your German better than your English?

Then this may be your lucky day.

Frajo Ligmann, a school teacher near Aachen, Germany, has started to produce German language versions of the Joy Of Code videos. At time of writing, he has produced six videos already, which you can see on his Youtube channel. And he is working on more, which should appear as time goes on.

Producing videos is a lot of work and very time intensive, so be a bit patient if you’re itching to see more. If you’re happy to watch these in German, bookmark his page and leave him a comment, either on his page or right here below this post.

Many thanks to Frajo Ligmann for this amazing contribution to our community!


JoC #33: Playing Breakout! Collision detection

      Finagles’ 8th Rule: Teamwork is essential; it allows you to blame someone else.

Today, we’re finally getting our breakout game into a playable state! Yes!!

See how to implement functionality to recognise when the ball hits a block, and make the block disappear. This is really the centrepiece of our program – from now on, everything else is detail.

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Concepts discussedcollision detection, removing an object from the world

Download (scenario as of beginning of this episode):

JoC #32: Pretty pictures with while loops

      90% Rule of Project Schedules: “The first 90% of the task takes 90%
      of the time, and the last 10% takes the other 90%.”
            — (source unknown) 

One more time, discussions of loops.

Loops are such an important concept, and there are so many variations, that it is really important to get practice with them and get them properly into your head. To this end, we’re looking one more time at loops here before moving on to some new concepts in the next episode.

Today, we’re using a really important, fundamental loop pattern: A while loop with a simple loop counter. It looks like this:

    int i = 0;
    while (i < NUMBER)
        i = i + 1;

Watch the video, and try to memorize this pattern. It will come in handy later!

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Concepts discussedloops, while loop

Download (scenario as of beginning of this episode):

JoC #31: More loopiness

      The First Law of Programmer Creativity: “The cost of software maintenance 
      increases with the square of the programmer’s creativity.”
            — (source unknown) 

We continue with our breakout scenario, an also with our investigation of loops. Jumping right ahead, I show you both how to write a nested loop, and why and how never to do it.

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Concepts discussedloops, while loop


JoC #30: Introduction to loops

      Whatever begins, also ends.
            — Seneca
      (Seneca obviously didn’t know about getting your loop condition wrong …  — mik)

Today, we are introducing a new concept: loops. Or, if you want to know more precisely: the while loop.

But, as always, we’re not doing this by just talking about the theory in a vacuum – we actually need it to progress with one of our projects, the Breakout game that we have seen before.

Loops are a concept fundamental to all programming, so if you are a learner, pay close attention. You will need this again later!

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Concepts discussedloops, while loop