C++ Naming Conventions

[wswartzendruber]

So I'm working on a class library that uses Qt4 exclusively. QCA does this, and all of its classes have their own namespace. Qt4 itself doesn't put things in a namespace (it seems), but instead chooses to prefix everything with the letter Q. Which way is proper?

[drescherjm]

Which way is proper?

Both ways are fine.

There is some information about coding standards here:

http://www.parashift.com/c++-faq-lite/c ... #faq-27.12

[Mad Merlin]

So I'm working on a class library that uses Qt4 exclusively. QCA does this, and all of its classes have their own namespace. Qt4 itself doesn't put things in a namespace (it seems), but instead chooses to prefix everything with the letter Q. Which way is proper?

Both and neither. The best part about standards is that there's so many to choose from!

[dmitchell]

I suggest you use a namespace.

[doubleagent]

I suggest you use a namespace.

Seconded.

[drescherjm]

I suggest you use a namespace.

Seconded.

Although I have used this in the past one disadvantage is this makes your identifier names even longer well unless you use

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using namespace namespace_name

And it does not solve the problem of having multiple files of the same name.

On my latest 2 projects I have ditched using namespaces and moved to the vtk approach. I mean prepending the some short identifier to the beginning of all class and file names.

http://www.vtk.org/Wiki/VTK_Coding_Standards

In this my current Qt project is called StudyManager. And so all filenames and classes start with sm. So in one of the libraries of this project I have a class smStudy with its filenames Include/smStudy.h and src/smStudy.cxx

[Earthwings]

Using short namespaces without unnecessary nesting is the way to go in my opinion. Long/nested namespaces lead to -- in my opinion -- unreadable header files (where you really should not put any using declaration). At work I have to prefix everything with a 't' for "historic reasons", and I hate it with a passion

[Voltago]

At work I have to prefix everything with a 't' for "historic reasons", and I hate it with a passion

tUh... twhat tgood tis ta tprefix tif tyou tprefix teverything? That's exactly as braindead as that Microsoft-ish prefixing of all member variables with m_. How about somebody with time on their hands writes a little library to represent C/C++/Java in a canonical form and the option to apply coding and tabbing style as well as naming conventions like stylesheets... (of course the editor of choice then in turn would have to enforce that set of conventions to retain bijectivity)? Or is there something like that out there already?

[drescherjm]

braindead as that Microsoft-ish prefixing of all member variables with m_.

Hmm.

Even though I program in Qt now instead of MFC I still do that.

m_ = Class Member
g_ = Global or Static class variable

local does not have m_ or g_

[Voltago]

But do you really have that many variables (that of course have speaking names) around that you need that? And if you need a distinction for members, why not use the instance name as prefix? With IntelliSense (or whatever you call that functionality that pops up a list of choices as soon as you type 'this->' in most IDEs) that would probably ease coding as well.

[dmitchell]

Also, be aware of the possibility of namespace aliases:

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namespace long_namespace_name { ... }

namespace lnn = long_namespace_name;

[drescherjm]

Also, be aware of the possibility of namespace aliases

Thanks I was not aware of that. Thanks.

But do you really have that many variables (that of course have speaking names) around that you need that?

Probably not. Force of habit after writing somewhere between 600K and 800K lines of MFC code over the last 12 to 13 years...

I have dropped the C prefix from all classes but that was long ago even when writing MFC code. At some point I realized that was pointless and stopped that.