9618 · 12.2
Program Design — FAQ
Frequently asked questions for 9618 Program Design. Direct answers first, then deeper explanation — then practise with marking.
Is a structure diagram the same as a flowchart?
No, they serve different purposes. A structure diagram shows the decomposition of a problem into modules (the 'what'). A flowchart shows the sequence of execution, including steps, decisions, and loops (the 'how'). They are not interchangeable.
Why can't I just start coding? It feels faster.
For very small, trivial programs, you might get away with it. For any problem of even moderate complexity, coding without a design leads to disorganised, hard-to-read, and difficult-to-debug code. Time spent on design is saved many times over during debugging and maintenance.
What is the real difference between top-down design and stepwise refinement?
They are very closely related. Think of top-down design as the overall strategy: 'Start at the top and break it down'. Stepwise refinement is the process you use to execute that strategy: 'At each step, add more detail until the task is simple enough to code'.
Do I need to draw a structure diagram for every program in the exam?
No, you only need to create one if the question explicitly asks for it. However, you should always be thinking in terms of top-down design and modules when you plan your pseudocode answers, as it will lead to better-structured solutions that are easier to write and earn more marks.