Andre's Webpage

Due to project at the Constance University of Applied Sciences I got involved in writing Java applets. The basic idea was to create an interface which allows students to perform their laboratory exercises via the Internet right from their bed at home.

Here are some small programs which give you some idea how Java applications and applets are written.

1. Coefficient of correlation
The following command-line based application allows you to determine the coefficient of correlation regarding two test series (x,y). After starting the program, the values of each series are read into an array. Then the mean values and the coefficient of correlation are calculated. Looking at this small example you can see how easy runtime errors can be handled.

sta_a4.java (Java source code)

2. Demo Applet
Concerning this program I basically want to show how to create an applet. It has been written in order to hold a brief introduction about applet programming at my university. The program consists of an input and an output line. When you're entering a text into the input line, the same text will be displayed in the output window immediately. Nothing special, so far. However, if you select "Umgekehrt" at the selection box, the letters of your text will appear in reverse order. Pressing the "Loeschen" button you can clear both text lines. Furthermore, a parameter given from the html page allows you to change the color of the border.

applet1.java (Java source code)
applet1.zip (Click here to download zipped archive (source, classes, html) 10kB)

3. SINPLOT While playing around with graphics and math functions, I got the idea to create a tiny 3D plot. So I started writing a program which draws a function twice at different locations connecting each calculated point between the two curves. Though a real 3D plot would require distortion of the functions, my plot already had kind of like three-dimensional impression. At this point, I added some sliders to turn the picture horizontal (a) and vertical (b). As I was interested how other functions would effect the picture, two choices have been added which allow an independent selection of functions for each curve. Using a third slider (c) you can change the resulotion of calculations. Keep in mind, this program doesn't support real 3D distortion, but playing with it is very nice, anyway.

SINPLOT (Click here to start the applet (works best with any Browser !))
sinplot.java (Java source code)
sinplot.zip (Click here to download zipped archive (source, class, html) 5kB)

4. Gingerbread Man
The 'Gingerbread Man' is one of the most famous fractals. Actually, calculating this picture is easier than you would expect. It is a recursive algorithm and the color of a specific (x,y) tuple is determined by the number of iterations that are necessary to reach a certain result. With the applet I've written you will get a default view of the fractal. Clicking inside the picture will zoom in (just have a try -- it's really fun and you can get very interesting pictures!). To reset the applet, hit the reload button of your browser. I have put detailed information into the source code on how the algorithm works.

FRACTAL (Click here to run the applet (works best with Netscape 4.72 !))
fract.java (Java source code)
fract.zip (Click here to download zipped archive (source, class, html) 5kB)