Quick questions on The software development process - SQA National 5 Computing Science

The developer works out exactly what the program has to do before writing anything. The output is a clear description of the purpose (what the program is for), the scope and boundaries (what it will and will not do), and the functional requirements (the specific inputs, processes and outputs the program must provide). Getting analysis right matters because a misunderstanding here is expensive to fix later.

The developer plans how the program will meet the requirements. This produces design documents such as a structure diagram or flowchart showing how the problem breaks into parts, pseudocode describing the algorithm, and a wireframe sketching the user interface. Design turns "what" into a concrete plan a programmer can follow.

The developer writes the program code in a high-level language, translating the design into computational constructs (variables, selection, iteration and so on). This is the stage where the design actually becomes a running program.

The developer runs the program with carefully chosen test data to check it works correctly and to find errors. Testing uses normal, extreme and exceptional data and checks the program against every functional requirement from analysis.

The developer produces the written material that supports the software: a user guide that explains how to install and use it, and technical documentation that records how the program works for anyone who has to maintain it later.

The developer judges the finished program. The central question is fitness for purpose (does it do everything the requirements asked for?), along with efficiency, robustness and readability of the code.