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Dave Rudolf
Guest
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 Posted: Fri Mar 05, 2004 3:55 am Post subject: Circular references involving internal classes |
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Hey all,
I have a philosophical question for you folks -- that is, I don't really
need an immediate solution, but rather I am just curious.
Is there some way to make forward declarations for internal classes. The
situlation that I have is probably best illustrated with some code:
// legal forward declaration
class B;
// illegal forward declaration
// class B::Bi;
class A
{
B _b;
// B::Bi _bi;
};
class B
{
class Bi
{
};
A _a;
};
Let's forget that the above code is probably not the best design. Now, if I
want class A to handle references to class B, I can do the normal forward
declaration thing before class A, as above. But what if I want to reference
B's inner class, as suggested by the commented-out code? Is there any way to
do such a thing?
Of course, the work-around could be to move the inner class into it's own
class. Like I said, I'm just curious.
Dave
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Chris ( Val )
Guest
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| Posted: Fri Mar 05, 2004 11:27 am Post subject: Re: Circular references involving internal classes |
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"Dave Rudolf" <nuclearwhippingboy (AT) hotmail (DOT) com> wrote
| Quote: | Hey all,
I have a philosophical question for you folks -- that is, I don't really
need an immediate solution, but rather I am just curious.
Is there some way to make forward declarations for internal classes. The
situlation that I have is probably best illustrated with some code:
// legal forward declaration
class B;
// illegal forward declaration
// class B::Bi;
class A
{
B _b;
// B::Bi _bi;
};
class B
{
class Bi
{
};
A _a;
};
Let's forget that the above code is probably not the best design. Now, if I
want class A to handle references to class B, I can do the normal forward
declaration thing before class A, as above. But what if I want to reference
B's inner class, as suggested by the commented-out code? Is there any way to
do such a thing?
Of course, the work-around could be to move the inner class into it's own
class. Like I said, I'm just curious.
|
Use a pointer to the objects:
class B;
class Bi;
class A
{
B* _b;
Bi* _bi;
};
Cheers.
Chris Val
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Rob Williscroft
Guest
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| Posted: Fri Mar 05, 2004 11:35 am Post subject: Re: Circular references involving internal classes |
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Dave Rudolf wrote in news:104fuhe7ct02o21 (AT) corp (DOT) supernews.com:
| Quote: | Hey all,
I have a philosophical question for you folks -- that is, I don't
really need an immediate solution, but rather I am just curious.
Is there some way to make forward declarations for internal classes.
|
No, though you can do this:
class Outer
{
class Inner; /* kinda forward declare */
};
class Outer::Inner /* define */
{
};
| Quote: | The situlation that I have is probably best illustrated with some
code:
// legal forward declaration
class B;
// illegal forward declaration
// class B::Bi;
class A
{
|
This is illegal too, B is an *incomplete* type, you can declare
pointers and references to B (B*, B& etc) but not B's.
| Quote: | B _b;
// B::Bi _bi;
};
[snip] |
Rob.
--
http://www.victim-prime.dsl.pipex.com/
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