References to base class to access derived class only members

mirizar · #1 01-Dec-2005, 18:48

Hi!

Can a base class reference be used to access derived class-specific members? Note that the members are not part of the base class, only part of the derived class.

Thanks, Michelle

Paramesh · #2 01-Dec-2005, 20:15

If anyone had caught my previous post, sorry. That was wrong.
The answer is :
NO.

Paramesh.

Paramesh · #3 03-Dec-2005, 20:07

Quote:

Originally Posted by mirizar

Can a base class reference be used to access derived class-specific members? Note that the members are not part of the base class, only part of the derived class.

OOPS!!.
It seems that it is possible by static_cast.
My first post holds good!!!

Here is how we can do it:

Code:

static_cast<Derived*>(&reference_variable)->DerivedMember(arguments);

So, consider a base class like this:

CPP / C++ / C Code:

class base
{   
public:
    void printbase()
    {
        cout<<"Hello there from base...";
    }
};

A derived class:

CPP / C++ / C Code:

class derived:public base
{
public:
    void printderived()
    {
        cout<<"Hello there from derived..";
    }
};

In the main function, we can call the printderived function like this:

CPP / C++ / C Code:

    base *b = new base();

    static_cast<derived*>(b)->printderived();

Will print "Hello there from derived.."

But doing such thing is often due to a design flaw.
It is not recommended, and often leads to logical error.

Regards,

Paramesh.

mirizar · #4 03-Dec-2005, 20:40

Paramesh:

That makes sense! Thanks a lot for the input. I agree that this is not the best way to do things.

Thanks, Michelle

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Rate This Thread
Rate This Thread:

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Fluid + class derived from Fl_Window	iga	FLTK Forum	11	31-May-2005 03:02
GIMcontacts - a gim fltk fluid venture	cable_guy_67	FLTK Forum	0	14-Feb-2005 14:18
calling abstract base class method calls draw instead	achoo	FLTK Forum	1	19-Dec-2004 09:38
Error C2146: syntax error : missing ',' before identifier 'C4'	mattchew008	CPP / C++ Forum	2	19-Dec-2004 06:06

References to base class to access derived class only members

Re: References to base class to access derived class only members

Re: References to base class to access derived class only members

Re: References to base class to access derived class only members