To work on your own computer, you'll need to download DrRacket version 5.3.
We will use a special language designed for cs019. This is shared with cs173, so you can learn more about it here.
You can find the crossbowman and longbowman example that illustrate how to use abstract class here. Note that these are different versions of the same code intended to show steps to create a superclass. They will not compile when put under the same directory, unless you compile only an individual file (Shift + F5 in DrJava).