RE: using keyword problem

RE: using keyword problem

[L.Suresh]

The using-declaration is used to bring every declaration with a given
name into scope. Here when you say A::S, there is no namespace "A", it
is the name of the class.

Try the code below. 

class A
{
public:
    struct S
    {
        int x;
    };
};

int Method()
{
    A::S s;
    s.x = 1;
    return s.x;
};


Thanks,
L.Suresh

Re: using keyword problem

[Eljay Love-Jensen]

Hi Artur,

The "using" keyword is for bring identifiers from one namespace available 
in the current namespace.

For example:
using std::cout; // cout is now accessible, without the std:: qualifier.
using namespace std: // the whole std:: uberverse is accessible.  Avoid 
collisions!

A class and a struct or sort of like namespaces, and also not like namespaces.

You want to do this...

class A
{
public:
     struct S
     {
         int x;
     };
};

int Method()
{
     typedef A::S S; // using A::S is no good here.

     S s;
     s.x = 1;
     return s.x;
};

HTH,
--Eljay

using keyword problem

[Artur Szostak]

Why does the following code not compile under GCC?
Is this not valid C++?

class A
{
public:
	struct S
	{
		int x;
	};
};

int Method()
{
	using A::S;

	S s;
	s.x = 1;
	return s.x;
};


When compiling the above code as is from source file main.cxx the following 
output is generated:

$ g++ main.cxx -o test
main.cxx: In function `int Method()':
main.cxx:12: parse error before `::' token
main.cxx:14: `S' undeclared (first use this function)
main.cxx:14: (Each undeclared identifier is reported only once for each
   function it appears in.)
main.cxx:15: `s' undeclared (first use this function)
$


-- 

Artur Szostak

Physics Department
University of Cape Town
Rondebosch
7701
South Africa

Work: +27 21 650 3356
Mobile: +27 82 297 9502
Email: artur@alice.phy.uct.ac.za   or  artursz@iafrica.com