question on operator ( ) overloading

[xuatla]

Hi,

I have a class myClass, and want to define operator () with it. But I
don't want to change the class itself (e.g., sometime the class is
defined by other people and I cannot change it), but want to define it
outside the class. Is it possible to do so?

e.g.,

class myClass
{
//.....

data_type operator [] (size_t i){
//...
} ;

} ;

data_type operator () (const myClass& c, size_t i)
{
return c[i];
}

When I compiled this, I got an error:

error: `data_type operator()(const myClass&, size_t)' must be a
nonstatic member function.

Google gives:
An overloaded `operator ()' must be a non-static member function.

Does it mean that operator () cannot be overloaded out of class?

Thanks.

-X

[Victor Bazarov]

"xuatla" <xu****@gmail.comwrote...

I have a class myClass, and want to define operator () with it. But I
don't want to change the class itself (e.g., sometime the class is defined
by other people and I cannot change it), but want to define it outside the
class. Is it possible to do so?

No.
V
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[Daniel T.]

In article <ea**********@daisy.noc.ucla.edu>, xuatla <xu****@gmail.com>
wrote:

Hi,

I have a class myClass, and want to define operator () with it. But I
don't want to change the class itself (e.g., sometime the class is
defined by other people and I cannot change it), but want to define it
outside the class. Is it possible to do so?

e.g.,

class myClass
{
//.....

data_type operator [] (size_t i){
//...
} ;

} ;

data_type operator () (const myClass& c, size_t i)
{
return c[i];
}

When I compiled this, I got an error:

error: `data_type operator()(const myClass&, size_t)' must be a
nonstatic member function.

Google gives:
An overloaded `operator ()' must be a non-static member function.

Does it mean that operator () cannot be overloaded out of class?

Yes. It must be a non-static member function.