The Iterative Development Process

Part of: Creative Development

A Process, Not a Straight Line The development process is the set of steps used to create a program. AP CSP describes four phases that are repeated, not done once: - Investigating : understand the problem and the users. - Designing : plan the structure, inputs, and outputs. - Prototyping : build a working but incomplete version. - Testing : check whether it meets the requirements. Because software is hard to get right the first time, the process is iterative and incremental . Iterative means you cycle through the phases repeatedly. Incremental means you add a little functionality at a time, checking as you go. Building Up One Step at a Time Imagine a tool that should sum only the even numbers in a list. Rather than writing everything at once, you build it incrementally. A first increment might just read and echo the numbers; a second adds the even check; a third adds the sum. Here is a later increment that keeps even values and totals them: Each increment is checked before the next is added, so a mistake is caught while the change is still small. Feedback Loops After each increment you gather feedback, from tests, teammates, or users, and feed it back into the next cycle. This feed

Challenge: Sum of Even Numbers