c structure doesn't allow static member while c++ does

Question

Today, i was a little bit surprised about the behavior of c structure vs c++ structure.

struct nod
{
    static int i;
};

int main()
{

    return 0;  
}

The above program works perfectly.

BUT,

When the same program is run in C environment, it is giving the error:

prog.c:3: error: expected specifier-qualifier-list before ‘static’

see here: http://ideone.com/2JRlF

Why it is so?

How would you define it? C has no scope resolution operator. — chris, Jun 21 '12 at 13:11
Huh? Maybe...because..C doesn't allow static members? It's just a feature C doesn't have, there is no certain *why* to it. You could also try to define a class, namespace or operator overload in C and ask *"why it not work?"*. It's just a different language with different features, that's it. — Christian Rau, Jun 21 '12 at 13:15
It's just that `static` isn't defined this way in C. You can, however, define it yourself to make it work: just `#define static`, and off you go! (No, of course I'm not serious!) — Jerry Coffin, Jun 21 '12 at 13:32

score 7 · Accepted Answer · edited May 23 '17 at 12:20

7

Because in C++, structs are just classes with default visibility of public. So in C, the struct is only a aggregation of data, which does not know anything about the fact that it could be percieved as standalone type.

See also What are the differences between struct and class in C++

edited May 23 '17 at 12:20

Community

1
1

answered Jun 21 '12 at 13:12

Jonas Schäfer

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Steve Jessop · Answer 2 · 2012-06-21T17:11:29.920

Each C++ class has its class namespace, so you can refer to that static data member as nod::i from outside the class namespace, and just plain i inside it. C has no namespace scopes, and there's no code "in" C structs, so there's no way to hide globals in namespaces or to refer to them by their unqualified name in their own scope. So there was no motivation in C to have the thing that in C++ is called static data members.

Just do int nod_i;.

score 3 · Answer 3 · answered Jun 21 '12 at 13:12

3

static in C only has the meaning of internal linkeage. Don't think of a C-struct as you would of a struct or a class in C++. It's just an aggregator, not the OOP construct.

As C doesn't have classes, this use of static doesn't make sense.

answered Jun 21 '12 at 13:12

Luchian Grigore

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c structure doesn't allow static member while c++ does

3 Answers3