enum in a subclass ...

[danjiun]

Hi friends,
i want to ask if somebody know a way to arrange next circumstance :
Inside a base class we have a enum :
class Base {
public:
enum Enum { obj1, obj2, obj3 };
Base();
};

class Deriv : public Base
{
public:
Deriv();
};

Originary i have all packet, so i have many places in my code in which i access my class like :
function(Deriv::obj1);
?
I tried also to make something like :
class Deriv : public Base
{
public:
typedef Base::Enum Enum;
Deriv();
};

But this not help very much.
Thanks for any help.
Daniel

[coder777]

But this not help very much.

What's the problem with Deriv::obj1 or respectively Base::obj1?

[Bhavith]

Hi danjiun ,
Can you please explain what problem are you facing .
While writing code use <code> </code> blocks .

[danjiun]

Thanks for you reply.
I have defined a function as :

 
void function(Deriv::Enum o);

but, of course Deriv not contains directly enumeration Enum.
So, compiling, compilator throw a "undefined reference ..." say it not have

void function(Base::Enum o);

because, i make a use of this function with :

function(Deriv::obj1);

So, my question is next : it is possible to arrange Deriv in a way that i still can use Deriv, and enumeration elements like there are at Deriv ?
I wish to no need to write

function(Base::obj1);

for have it more clean.
greatings, Daniel

[Peter87]

The code that you have posted looks fine. No need to use typedef or anything. The error "undefined reference" means it can't find the definition of the function.

[danjiun]

Hi
but it not compile.
For a moment, i redefine for :

 
void function(Base::Enum o);

and like this it compile.
I dont know if it is a intrinsic problem of C++. Compiler is gcc x86, at 64 bits inside Linux.
Or may be i be am wrong. I already program 17 years in C++, and this is a first time i encounter a problem like this. Now i use already 1-2 years, C++11
Thanks for any help.
Daniel

[Peter87]

This code works fine.

class Base {
public:
	enum Enum { obj1, obj2, obj3 };
};

class Deriv : public Base {};

void function(Deriv::Enum o) {}

int main()
{
	function(Deriv::obj1);
}

Note that Deriv::Enum is the same type as Base::Enum so it doesn't matter which one you write.

[danjiun]

Thanks.
Before it not compile.
But, after i recompile , it works also.
Thanks, Daniel

[coder777]

I still don't see your problem. You should be able to access Enum via Deriv and/or Base without problems.

Provide an example where the problem actually occurs.

[danjiun]

May be, previously not work because i use Qt, and it use a intermiddle file.
Precisely, function its a function as a signal :

signals:
    void tagOperation(TagExtHistorial::Operation op);

Qt produce additionally "moc"-files.
So , sometimes, if it appear strange errors, its good to recompile.
Daniel