The entry into the recursion starts with calculation algorithms such as n!, Fibonacci sequence, gcd and lcm and continues with recursive graphics. A prime example of recursion is the algorithm of the problem "Towers of Hanoi". However, the applet presented here has been using the knowledge of the data structure "stack" forward. At various examples such as term calculators, waiting rooms and car washs linear data structures List, Stack and Queue are demonstrated. It continues with examples of searching and sorting. Finally, tree structures are presented with various examples.

Starting with simple graphics (circle, triangle, square) for practicing graphics commands and dealing with elements such as selection and slider. Then follows the handling of strings and finally strings and graphics are combined in Hangmanprojekt.

We will proceed with a first introduction to object-oriented programming, following on from the previous graphic project. First you create a class ball. The ball is represented as a circle. The movement of the ball is done by erasing and drawing it in a new location. A class pool table presents a table represented by a rectangle and submits various methods to give back position and dimension of this table. A new class billiard ball is implemented as a subclass of the ball. In contrast to the ball a billiard ball knows a pool table and bounces off the edges. A new project draws figures (squares and circles of different size and color) on the canvas. Squares and circles are subclasses of the abstract class figure. An object of class figure can therefore be a circle or a square (polymorphism). If an object is clicked, it can be moved with the cursor keys.

The entry into the network programming is demonstrated by several examples. IYou usually start with the (simpler) programming of clients before some of the servers become a subject. Simple examples are echo-echo client and server, time client and time server, chat client and chat server. At the end of the sequence the game Tic-Tac-Toe is discussed. The implementation of the client is quite simple (the player makes his selection by clicking on the appropriate button), implementing the server makes more trouble: it must on the one hand, all playing fields of the various clients store in a list and have a game plan.