By analyzing your problem in terms of objects, you can determine what classes need to be created and begin to take advantage of object-oriented technology. You can create a class using messages or directives. Directives are a new kind of REXX clause, and they are preferred over messages because the code is easier to read and understand, especially in large programs. They also provide an easy way for you to save your class definitions and share them with others using the PUBLIC option. Because of these advantages, directives is the technique we will use here.