Class / Member Class relationship?

[faisalee]

Hi Guys,

I have a question. Here goes:

class clsManager {
public:
int x;
int y;

}

class clsContainer {
public:
int a;
int b;
clsManager oManager;

}

So I have these two classes, first class is a member of second class.
Is it possible to to access members of class clsContainer from the
object oManager ? How can it be done ?

Thanks & Best Regards.
Faisal.

[Greg Comeau]

In article <11************ *********@p79g2 000cwp.googlegr oups.com>,
faisalee <fa******@gmail .comwrote:

>I have a question. Here goes:

class clsManager {
public:
int x;
int y;

}

class clsContainer {
public:
int a;
int b;
clsManager oManager;

}

So I have these two classes, first class is a member of second class.
Is it possible to to access members of class clsContainer from the
object oManager ? How can it be done ?

Not in any portable way. What problem are you trying to solve?
Perhaps there is an other solution barking up another tree.
--
Greg Comeau / 20 years of Comeauity! Intel Mac Port now in alpha!
Comeau C/C++ ONLINE == http://www.comeaucomputing.com/tryitout
World Class Compilers: Breathtaking C++, Amazing C99, Fabulous C90.
Comeau C/C++ with Dinkumware's Libraries... Have you tried it?

[john_andronicus]

faisalee wrote:

Hi Guys,

I have a question. Here goes:

class clsManager {
public:
int x;
int y;

}

class clsContainer {
public:
int a;
int b;
clsManager oManager;

}

So I have these two classes, first class is a member of second class.
Is it possible to to access members of class clsContainer from the
object oManager ? How can it be done ?

Add a pointer to a clsContainer to the clsManager class.

class clsManager {
public:
clsManager(clsC ontainer* c) : container(c) {}
int x;
int y;
clsContainer* container;
};

John

[BigBrian]

faisalee wrote:

Hi Guys,

I have a question. Here goes:

class clsManager {
public:
int x;
int y;

}

class clsContainer {
public:
int a;
int b;
clsManager oManager;

}

So I have these two classes, first class is a member of second class.
Is it possible to to access members of class clsContainer from the
object oManager ? How can it be done ?

Thanks & Best Regards.

I would question why you need to do this. Perhaps you could use the
construct that's described in 24.3 in the faq ( which I quote below
)...

A legitimate, long-term use for private inheritance is when you want to
build a class Fred that uses code in a class Wilma, and the code from
class Wilma needs to invoke member functions from your new class, Fred.
In this case, Fred calls non-virtuals in Wilma, and Wilma calls
(usually pure virtuals) in itself, which are overridden by Fred. This
would be much harder to do with composition.

class Wilma {
protected:
void fredCallsWilma( )
{
std::cout << "Wilma::fredCal lsWilma()\n";
wilmaCallsFred( );
}
virtual void wilmaCallsFred( ) = 0; // A pure virtual function
};

class Fred : private Wilma {
public:
void barney()
{
std::cout << "Fred::barney() \n";
Wilma::fredCall sWilma();
}
protected:
virtual void wilmaCallsFred( )
{
std::cout << "Fred::wilmaCal lsFred()\n";
}
};

[faisalee]

Hi Greg,

Thanks for the reply. Actully I am maintaining a project that was
written way back in 1998! Well talking about the main classes, it has
two of them,

DBMgr and DBOps

DBMgr is responsible for opening a connection to the SQL Database and
the DBOps manages the SQL Statements like Insert, Update / Delete etc.

The DBOps is a member class of DBMgr and in the Connection handle is
assigned to the DBOps object through its constructor.

Now the problem is that other classes uses a ref object of the DBOps to
perform DB Operations directly. There are times when the DB Connection
gets broken and DBOps dont know how to connect / reconnect back. Since
only DBMgr knows how to do it.

So I thought if I can get a ref of DBMgr inside DBOps class, I can just
call the connect method which will automatically assign the connection
handle to the required classes.

I hope I was able to explain clearly... I dont see if there is any
other way.

Oh yes I thought of defining the Connect / Disconnect method as static
but then I will have to change all the member variables used inside
them as static too... THIS I dont want to do :-)

Is there any other way to do this? Or usin this cyclic relation is the
only way?

Best Regards,
Faisal.

Greg Comeau wrote:

In article <11************ *********@p79g2 000cwp.googlegr oups.com>,
faisalee <fa******@gmail .comwrote:

I have a question. Here goes:

class clsManager {
public:
int x;
int y;

}

class clsContainer {
public:
int a;
int b;
clsManager oManager;

}

So I have these two classes, first class is a member of second class.
Is it possible to to access members of class clsContainer from the
object oManager ? How can it be done ?

Not in any portable way. What problem are you trying to solve?
Perhaps there is an other solution barking up another tree.
--
Greg Comeau / 20 years of Comeauity! Intel Mac Port now in alpha!
Comeau C/C++ ONLINE == http://www.comeaucomputing.com/tryitout
World Class Compilers: Breathtaking C++, Amazing C99, Fabulous C90.
Comeau C/C++ with Dinkumware's Libraries... Have you tried it?

[faisalee]

Thanks Jhon,

I will give it a try :-)

Regards,
Faisal.

jo************* @hotmail.com wrote:

faisalee wrote:

Hi Guys,

I have a question. Here goes:

class clsManager {
public:
int x;
int y;

}

class clsContainer {
public:
int a;
int b;
clsManager oManager;

}

So I have these two classes, first class is a member of second class.
Is it possible to to access members of class clsContainer from the
object oManager ? How can it be done ?

Add a pointer to a clsContainer to the clsManager class.

class clsManager {
public:
clsManager(clsC ontainer* c) : container(c) {}
int x;
int y;
clsContainer* container;
};

John

[Default User]

faisalee wrote:

Thanks Jhon,

Please don't top-post. See the newsgroup FAQ under "How to Post".


Brian