C ++的类图

Question

Guys ! I understood that my previous question did not meant to you guys as per my intentions. I apologize for the same.

Let me pose in a different way.

Take my case, yesterday I faced an interview.

The guy out there asked me that he is trying to develop an application similar to google maps for his windows mobile device.

He asked me to come up with a class diagram for the application.

It was like a bouncer for me.

In such cases, what should be my approach ? where should I start ? How should I look at the problem ?

I hope this is better understood.

I request you to answer me considering that I am an amateur C++ developer who has never worked on any projects from the analysis & design phase

and doesn't know abc's of design.

Thanks,

krisssam

Answer 1

First you need a clear understanding about what you should be written. Formulate that understanding in English. Now every noun is a candidate for a class. Every verb is a candidate for a method. and nouns that appear in the same sentence are candidates for association.

This sounds quite simple. That's because I simplified it a lot. Actually there is much more to it. Getting a clear understanding about what should be written alone is challenging. If you are interested I suggest reading a book on object oriented analysis and design.

Answer 2

Maybe a bit overkill for an interview, but even there I would still go for 1 and 3 and start with 4.

1. ask as much specifications as possible, so you know what is expected
2. When possible/needed, make use cases to get a clear view on how it will be used
3. Start high level, focus on the main features. Look for preferably less than 6 players (modules) and try to see how they interact. Define responsabilites and interfaces.
4. Break up these players in submodules and see how these interact (also define responsabilites and interfaces). Repeat until you have implementable entities (classes)
5. in parallel with 4, for architecture, see how it will be deployed and what language/frameworks/libraries are needed/available.

For google-maps, I assume that players could be the map-database, the map-viewer, the user-input, the search-engine, but I'm not a GUI/GIS/mobile expert.

Answer 3

定义软件每个组件将要承担的职责，然后围绕这些职责充实类。

Answer 4

It doesn't relate to the language. Class diagram - means you need to identify the major objects that "plays" in this app.

The map object and it's data members and actions

the icon objects and it's data members and actions ect...