class vs namespace?

[dean]

Hi all,

We have a few existing classes that we want to put into either another
class or a namespace, so that we can avoid naming conflicts. As far as
I can see the syntax is identical from a usage perspective.

Does anyone have an opinion on this either way?

Thanks

Dean

[Jakob Bieling]

Re: class vs namespace?

dean <deanbrown3d@ya hoo.comwrote:

Hi all,
>
We have a few existing classes that we want to put into either another
class or a namespace, so that we can avoid naming conflicts. As far as
I can see the syntax is identical from a usage perspective.
>
Does anyone have an opinion on this either way?

For your purpose, namespaces are the way to go. You can reopen a
namespace and add stuff across translation units. You cannot do this
with classes. In addition, using a class implies that you can create an
instance of that class, which, as I understood it, is not the case.

hth
--
jb

(reply address in rot13, unscramble first)

[Rolf Magnus]

Re: class vs namespace?

Jakob Bieling wrote:

dean <deanbrown3d@ya hoo.comwrote:

>Hi all,
>>
>We have a few existing classes that we want to put into either another
>class or a namespace, so that we can avoid naming conflicts. As far as
>I can see the syntax is identical from a usage perspective.
>>
>Does anyone have an opinion on this either way?

>
For your purpose, namespaces are the way to go. You can reopen a
namespace and add stuff across translation units. You cannot do this
with classes. In addition, using a class implies that you can create an
instance of that class, which, as I understood it, is not the case.

Also, you can use using-declarations with namespaces, and AFAIK that's not
possible with classes, at least not if you don't derive from them.

[dean]

Re: class vs namespace?

So what to do about member variables of the class, if we use a
namespace instead? I mean, how can one hide a private variable and just
allow accessor (get and set) functions? Put the member variable outside
of the namespace but in the same unit as the namespace?


Rolf Magnus wrote:

Jakob Bieling wrote:
>

dean <deanbrown3d@ya hoo.comwrote:

Hi all,
>
We have a few existing classes that we want to put into either another
class or a namespace, so that we can avoid naming conflicts. As far as
I can see the syntax is identical from a usage perspective.
>
Does anyone have an opinion on this either way?

For your purpose, namespaces are the way to go. You can reopen a
namespace and add stuff across translation units. You cannot do this
with classes. In addition, using a class implies that you can create an
instance of that class, which, as I understood it, is not the case.

>
Also, you can use using-declarations with namespaces, and AFAIK that's not
possible with classes, at least not if you don't derive from them.

[Fred Zwarts]

Re: class vs namespace?

"dean" <deanbrown3d@ya hoo.comwrote in message news:1158332731 .153079.82250@b 28g2000cwb.goog legroups.com...

So what to do about member variables of the class, if we use a
namespace instead? I mean, how can one hide a private variable and just
allow accessor (get and set) functions? Put the member variable outside
of the namespace but in the same unit as the namespace?

I would think the other way around.
Put the private variable in the same namespace but in another unit
(the unit in which you write the body of the get and set functions).
The advantage above a class implementation is that the private variables
are not even declared in the header file.
The header file discloses nothing about the implementation,
it has only the interface

Fred.Zwarts.

Rolf Magnus wrote:

>Jakob Bieling wrote:
>>

dean <deanbrown3d@ya hoo.comwrote:
>Hi all,
>>
>We have a few existing classes that we want to put into either another
>class or a namespace, so that we can avoid naming conflicts. As far as
>I can see the syntax is identical from a usage perspective.
>>
>Does anyone have an opinion on this either way?
>
For your purpose, namespaces are the way to go. You can reopen a
namespace and add stuff across translation units. You cannot do this
with classes. In addition, using a class implies that you can create an
instance of that class, which, as I understood it, is not the case.

>>
>Also, you can use using-declarations with namespaces, and AFAIK that's not
>possible with classes, at least not if you don't derive from them.

>

[Jakob Bieling]

Re: class vs namespace?

dean <deanbrown3d@ya hoo.comwrote:

Rolf Magnus wrote:

>Jakob Bieling wrote:

>>dean <deanbrown3d@ya hoo.comwrote:

>>>We have a few existing classes that we want to put into either
>>>another class or a namespace, so that we can avoid naming
>>>conflicts. As far as I can see the syntax is identical from a
>>>usage perspective.
>>>>
>>>Does anyone have an opinion on this either way?

>> For your purpose, namespaces are the way to go. You can reopen a
>>namespace and add stuff across translation units. You cannot do this
>>with classes. In addition, using a class implies that you can
>>create an instance of that class, which, as I understood it, is not
>>the case.

>Also, you can use using-declarations with namespaces, and AFAIK
>that's not possible with classes, at least not if you don't derive
>from them.

So what to do about member variables of the class, if we use a
namespace instead? I mean, how can one hide a private variable and
just allow accessor (get and set) functions? Put the member variable
outside of the namespace but in the same unit as the namespace?

I think I am not following. You said you have several classes and
want to put them into a namespace (or class, but let's just stick to the
namespace now) to avoid naming conflicts:

class A { int a; };
class B { int b; };

becomes

namespace dean
{
class A { int a; };
class B { int b; };
};

As you can see, your classes do not change. Their members stay right
where they are. You only introduce a new namespace and put the stuff in
there.

Apologies, if I am misunderstandin g you.

hth
--
jb

(reply address in rot13, unscramble first)

[Default User]

Re: class vs namespace?

dean wrote:

So what to do about member variables of the class

Please don't top-post. Your replies belong following or interspersed
with properly trimmed quotes. See the majority of other posts in the
newsgroup, or the group FAQ list:
<http://www.parashift.c om/c++-faq-lite/how-to-post.html>




Brian

[dean]

Re: class vs namespace?

I have no idea what to top-post means. And anyway, what are you adding
to this discussion?


Default User wrote:

dean wrote:
>

So what to do about member variables of the class

>
>
>
Please don't top-post. Your replies belong following or interspersed
with properly trimmed quotes. See the majority of other posts in the
newsgroup, or the group FAQ list:
<http://www.parashift.c om/c++-faq-lite/how-to-post.html>
>
>
>
>
Brian

[Noah Roberts]

Re: class vs namespace?


dean wrote:

I have no idea what to top-post means. And anyway, what are you adding
to this discussion?

You need to read the webpage to which you where directed.

[dean]

Re: class vs namespace?

Rolf - for better or worse, the company agreed not to use "using
namespace", but rather add the scope prefix onto each member, e.g.
CMyClass::MyFun c or CMyNamespace::M yFunc.

Dean

Rolf Magnus wrote:

Jakob Bieling wrote:
>

dean <deanbrown3d@ya hoo.comwrote:

Hi all,
>
We have a few existing classes that we want to put into either another
class or a namespace, so that we can avoid naming conflicts. As far as
I can see the syntax is identical from a usage perspective.
>
Does anyone have an opinion on this either way?

For your purpose, namespaces are the way to go. You can reopen a
namespace and add stuff across translation units. You cannot do this
with classes. In addition, using a class implies that you can create an
instance of that class, which, as I understood it, is not the case.

>
Also, you can use using-declarations with namespaces, and AFAIK that's not
possible with classes, at least not if you don't derive from them.

[dean]

Re: class vs namespace?

Fred - that is a very good idea. Nice implementation hiding.

Thanks

Dean



Fred Zwarts wrote:

"dean" <deanbrown3d@ya hoo.comwrote in message news:1158332731 .153079.82250@b 28g2000cwb.goog legroups.com...

So what to do about member variables of the class, if we use a
namespace instead? I mean, how can one hide a private variable and just
allow accessor (get and set) functions? Put the member variable outside
of the namespace but in the same unit as the namespace?

>
I would think the other way around.
Put the private variable in the same namespace but in another unit
(the unit in which you write the body of the get and set functions).
The advantage above a class implementation is that the private variables
are not even declared in the header file.
The header file discloses nothing about the implementation,
it has only the interface
>
Fred.Zwarts.
>

Rolf Magnus wrote:

Jakob Bieling wrote:
>
dean <deanbrown3d@ya hoo.comwrote:
Hi all,
>
We have a few existing classes that we want to put into either another
class or a namespace, so that we can avoid naming conflicts. As far as
I can see the syntax is identical from a usage perspective.
>
Does anyone have an opinion on this either way?

For your purpose, namespaces are the way to go. You can reopen a
namespace and add stuff across translation units. You cannot do this
with classes. In addition, using a class implies that you can create an
instance of that class, which, as I understood it, is not the case.
>
Also, you can use using-declarations with namespaces, and AFAIK that's not
possible with classes, at least not if you don't derive from them.

[Kai-Uwe Bux]

Re: class vs namespace?

dean wrote [top posting corrected]

Default User wrote:

>dean wrote:
>>

So what to do about member variables of the class

>>
>>
>>
>Please don't top-post. Your replies belong following or interspersed
>with properly trimmed quotes. See the majority of other posts in the
>newsgroup, or the group FAQ list:
><http://www.parashift.c om/c++-faq-lite/how-to-post.html>
>>

I have no idea what to top-post means.

Top posting is to put your answer above the text that you are replying to.
It is frowned upon in this news group -- that's a cultural thing.

And anyway, what are you adding to this discussion?

E.g., that you might benefit from reading the FAQ (generally a good idea and
part of netiquette).


Best

Kai-Uwe Bux

[dean]

Re: class vs namespace?

Gosh! Clearly this is a very important issue for some people so I
apologise to them. I was replying to two people at the same time, not
just one - both of them had good responses. Should I have just quoted
one of them?



Kai-Uwe Bux wrote:

dean wrote [top posting corrected]
>

Default User wrote:

dean wrote:
>
So what to do about member variables of the class
>
>
>
Please don't top-post. Your replies belong following or interspersed
with properly trimmed quotes. See the majority of other posts in the
newsgroup, or the group FAQ list:
<http://www.parashift.c om/c++-faq-lite/how-to-post.html>
>

I have no idea what to top-post means.

>
Top posting is to put your answer above the text that you are replying to.
It is frowned upon in this news group -- that's a cultural thing.
>
>

And anyway, what are you adding to this discussion?

>
E.g., that you might benefit from reading the FAQ (generally a good idea and
part of netiquette).
>
>
Best
>
Kai-Uwe Bux

[Default User]

Re: class vs namespace?

dean wrote:

I have no idea what to top-post means.

1. I explained it. Here it is again: Your replies belong following or
interspersed with properly trimmed quotes.

2. The FAQ goes over it as well. Did you read it?

And anyway, what are you adding to this discussion?

I'm helping you to get help by posting correctly. It so happens that
I've automated things a bit, so it's easy for me to quickly post the
information. I do that so others don't.




Brian

[Noah Roberts]

Re: class vs namespace?


dean wrote:

Gosh! Clearly this is a very important issue for some people so I
apologise to them.

Usually when you want to apologise to someone you don't do the thing
you are apologising for at the same time; makes you appear inconcere.
If you aren't sorry then don't apologise (many here will end up
killfiling you) and if you are sorry then you won't do it again and
you'll try to learn how to communicate in the group effectively.
You've been given the resources to learn and now know that yes, this is
an important issue. Now you'll either stop top-posting or you won't.
You're decision will have an impact on how people percieve you in the
group and the quality and quantity of answers you recieve.