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Question on Use Case

+3 votes
The exact scope of a use case is a little unclear to me. How large or small should the goal of the use case be? Is something as small as opening a menu valid for a use case? What about something as large as completing a long game or another complicated task?
asked Sep 1 in CSC 285 (F17) by Jack Cannell (437 points)

3 Answers

+2 votes
Page 77 of OOAD, "Q: Then my system will have a use case for every goal it accomplishes?

A: Exactly! if your system just does one single thing, you'll probably only need one use case. If it does ten or fifteen things, then you're going to have a lot of use cases."

The idea is for every problem you are solving you should have a use case. If we design a game builder then the use case would be the client who needs to design their own games. If we need to create a new abstract class for this project we could be the external initator, but the idea of use cases are really to gather requirements for bigger projects. So I suppose the best way to use use cases is to use as many as you need to make sure you have as many requirements that you can gather and the clearest picture of what you are designing. In theory you could be able to create hundreds of use cases, but most problems are so small we handle them.
answered Sep 2 by Daniel Zwiener (3,754 points)
+2 votes
Yeah, it's a bit tricky for a game.  This "use case" stuff is much more commonly applied to business-oriented software.

I would say that in our case opening a menu is too small of a task to deserve its own use case.
I think that "playing the game" would be a reasonable use case, even though it is somewhat large.  However, you don't need to go into every detail of exactly everything the player will see and click on, but your use case should provide an overview of how the player interacts with the game.  Hopefully such a use case will help enlighten some of the requirements for the software development of building the game...
answered Sep 4 by Forrest Stonedahl (3,438 points)
+2 votes
For our scope of one of the use cases we wrote, we got enough detail to show what someone would see and be able to do at different points of the game. For instance, we started with our menu screen and what the player will be able to do within that screen and where they can "go" as in where the different options lead to.
answered Sep 5 by Dylan Hart (1,385 points)
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