A program shell has been provided in the curriculum as SortStep.java (the main test method), and QuadraticSorts.java (the sort class template).

The program asks the user to select a sorting algorithm, fills the array with an amount of data chosen by the user, calls the sorting algorithm, and prints out the data after it has been sorted.

At this point, each sorting algorithm has been left as a method stub. A stub is an incomplete routine that can be called but does not do anything yet. The stub will be filled in later as each algorithm is developed and understood.

Stub programming is a programming strategy. It allows for the coding and testing of algorithms in the context of a working program. As each sorting algorithm is completed, it can be added to the program shell and tested without having to complete the other sections.

This stepwise development of programs using stub programming will be used extensively in future lessons.