SQA National 5 Computing Science

## Development methodologies A development methodology is an agreed way of organising the work of making software, so that it is carried out in a planned order and not by trial and error. ### Iterative development Software is developed in a sequence of phases, and the sequence is an **iterative development process**: a later phase can send the developer back to an earlier one, and the cycle is repeated until the program is right. The phases are: 1. Analysis 2. Design 3. Implementation 4. Testing 5. Documentation 6. Evaluation Analysis finds out what the program has to do. Design plans a solution before any code is written, using a structure diagram, a flowchart or pseudocode. Implementation is writing the program in a programming language. Testing runs it with chosen data to find errors. Documentation records the program for the people who will use or maintain it, for example a user guide or a description of how the code works. Evaluation judges the finished program against what was asked for. Each phase is allowed to feed back into the ones before it. A test that shows the program crashes on an empty input sends the developer back to implementation to add a check. An evaluation that shows the client needs a report the program does not produce sends them back to analysis, and then design, before the new feature is coded. An iterative approach is needed whenever the requirements are unclear at the start, whenever the client changes their mind, and whenever testing finds a…