CODEWITHSUNDEEP
c++namespacesstatic-functions
XtremeCold
XtremeCold

Reputation: 27

Scope of Namespace

I'm a C developer and just recently switch to C++ so namespace is new thing to learn. The A class has a static method validate(), thus it can only access static variables or constants of the A class. But if the A.cpp has a constant defined in a namespace, the val() is able to use the constant and the code below was compiled properly.

A.h

class A
{
    public:
    A();
    static bool validate(const int num);
};

A::A()
{
    // Do nothing. Just an example.
}

A.cpp

namespace A_local_constants
{
    const int val = 1;
}

using namespace A_local_constants;

bool A::validate(const int num)
{
    return (num == val);
}

So my question is:

  1. Why is the static function validate() able to use the non-static constant val?

  2. Where is the val created in the memory?

  3. What scope is this constant?

  4. Is it always created in the memory without the A object being created?

Upvotes: 1

Views: 93

Answers (1)

Arun
Arun

Reputation: 2102

1) "using namespace A_local_constants;" this statement drags out all symbols defined within A_local_constants, hence bool A::validate(const int num) can refer to val.

2) Global memory

3) The scope of this contant is within A_local_constants and also will be made visible in all those places where we use "using namespace A_local_constants" or "using namespace A_local_constants::val"

4) There is no relation between class A and the constant val.

Note: "using namespace some_name_space" should be used judiciously as they may unnecessarily pollute the current namespace.

Upvotes: 1

Related Questions