This calculator is designed to illustrate the main features of modern desktop calculators. In particular, the statistics functions for mean and standard deviation are implemented.
The calculator can run either as an applet or as a standalone application.
If you want to improve the calculator (e.g. by adding some features) have a look at the Parser class, which does all the function evaluations and the CalculatorApplet class, which handles the GUI. Note, however, that there is a better version of this calculator as a Java 2 5.0 Calculator.
You will need a java plugin for this web page to work properly. If you don't have one, you can get one from Sun Microsystems. Some java plugins, notably the ones from Microsoft, but also some older plugins won't work with the java applet on this page.