Kara offers a playful introduction to fundamental concepts of programming. Kara is a ladybug that lives in a simple world with trees, leafs and mushrooms.

The rules of Kara’s world are simple:

Actions

• Kara can move around with move() (Kara can push a mushroom, can step on leafs but can’t walk through trees)
• Kara turns left or right with turnLeft() or turnRight()
• Kara puts down a leaf with putLeaf()
• Kara picks up a leaf with removeLeaf()

Sensors

• Kara checks if he stands on a leaf with onLeaf()
• Kara checks if there is a tree with treeFront(), treeLeft(), or treeRight()
• Kara checks if there is a mushroom in front with mushroomFront()

A Sample Exercise

Kara is placed in the following world setup and must be programmed to collect all leafs until he reaches the tree:

One solution would be as follows:

Kara Collects Leafs

while (!treeFront()) {

  if (onLeaf()) {
    removeLeaf();
  }
  
  move();
}

Kara Versions - Which Kara Should I Use?

Kara has many different versions. The original Kara is designed as a finite state machine with a purely graphical program editor. See the full list of available Kara versions.

I usually prefer to start directly with writing code in the Java language. Now there are quite a few possible editors/libraries:

GreenfootKara (Java)

Since I really like the editor of the Greenfoot IDE I decided to create a Kara version that works with Greenfoot, it is called GreenfootKara. In addition to this I wrote an entire beginners course of 16-20 lessons with exercises and handouts to go along with GreenfootKara. You can find the links to the German and English versions on the GreenfootKara page.

GameGridKara (Java)

Sometimes, especially if time is too short, it might be good to directly start with a professional development environment like Eclipse or NetBeans. Since it was not possible to integrate Greenfoot into Eclipse/NetBeans, I had to find another solution. Altough, we could start JavaKara from Eclipse/NetBeans, there are just some things that are not possible (like programming an interactive Kara game). The solution was to port the code to work with a library called JGameGrid.

GameGridKara enables us to use Kara in any IDE of our choice by simply adding two jar files to a project. The link to GameGridKara with the adjusted beginners course in German and English can be found on the GameGridKara page.

JavaKara (Java)

JavaKara is the original editor. You can find the JavaKara download and resources here (in German).