Programming Forums - namespace vs struct

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Klarre

Dec 27th, 2006 9:11 AM

namespace vs struct

Usually when I want global functions in my C++ applications I do like this:

namespace Tool

{

        static inline int foo() {}

        static inline int bar() {}

}



int main()

{

        Tool::foo();

        Tool::bar();

}

Another more common way to achieve this result is by doing it this way:

struct Tool

{

        static inline int foo() {}

        static inline int bar() {}

};



int main()

{

        Tool::foo();

        Tool::bar();

}

So to my question: Is there a difference between them (have not checked the generated code yet)? Which one should I prefer and why?
Thanks for your thoughts!

/Klarre

peaceofpi

Dec 27th, 2006 1:20 PM

Well I'm no pro but I'm pretty sure the second one doesn't work. More like

struct Tool

{

        static inline int foo() {}

        static inline int bar() {}

};



int main()

{

        Tool hammer;

        hammer::foo();

        hammer::bar();

}

Hope I helped >_>

Klarre

Dec 27th, 2006 3:13 PM

Quote:

Originally Posted by peaceofpi (Post 121793)

Well I'm no pro but I'm pretty sure the second one doesn't work.

The functions are static and therefor you can call them without an object.

rsnd	Dec 27th, 2006 4:27 PM

I think namespaces are there to resolve naming conflicts for linker in different parts of the program. For example, if you had a function with declaration "int foo() {}" in one file of your program, you shouldnot be able to have the same thing somewhere else unless its in different namespace. This is vary useful in program organization in large programs. Should be nothing more and nothing less.

grumpy

Dec 27th, 2006 6:30 PM

Assuming all of your functions are static, there is no difference between the two approaches. A name of the struct (or class) is, in this context, a namespace. That is, among other things, why the syntax "Tool::foo();" works for calling Tool::foo() in both cases.

The example given by peaceofpi does not work, as the name of an object is not a namespace.

Eoin	Dec 27th, 2006 7:24 PM

I would suggest going with the namespace, from a practical point it means you don't have to declare everything you want to put into 'Tool' at the one point.

Plus, stylistically, I feel the namespace version more clearly expresses your intentions. Could be just me though.

prototype_angel

Dec 29th, 2006 3:28 AM

I would suggest going for the struct as you can do this
Tool a;
a.foo(); or something of that effect. You can also go for classes as you can inherit them. (but now you can also inherit them in structs) which can make your expansion easier. But if you won't make variables out of struct, it defeats the purpose and so it's cooler to use Namespace.

pegasus001

Dec 29th, 2006 11:43 AM

I guess that namespaces and structs are way too different. Most of their differences are in the way you concieve your program and the reusability of the code. You create a namespace when you create your own library or anything like that if you want to prevent nameclashes. You create struct if you have to abstract an object in the real life( because c++ treats structs and unions the same as classes).

DaWei

Dec 29th, 2006 12:40 PM

A namespace defines a scope. All its members are public; forget access specifiers. Unlike a class or a struct, it is open. That is, you can extend it later with more definitions. Also unlike a class or struct, the closing brace does not have a following semicolon.

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