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From: Fabio Ortiz <jfabio@mailhost.netrunner.net>
Subject: friend operator and the this pointer
Date: 1996/10/18
Message-ID: <3265ACC9.590D@mailhost.netrunner.net>#1/1
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Hi, I have the following:

class A
{
public:
	A( char* name );
	friend ostream& operator<<(ostream& o, A& a)
		{
			a.display( &o);
			return o;
		}
protected:
	char* myName;
private:
	virtual void display( ostream& o)
	{
		o << myName;
	}
}

class B: public A
{
public:
	B( int value, char* name );
	ostream& operator<<(ostream& o, B& b)
	{
		b.display( o );
		return o;
	}
protected:
	int myValue;
private:
	virtual void display( ostream& o)
	{
		o << (A*) this;
		o << myValue;
	}

class C: public B
{
public:
	C( long number, int value, char* name);
	ostream& operator<<(ostream& o, C& c)
	{
		o << c.display( ostream& o);
		return o;
	}
protected:
	long parameter;
private:
	virtual void display( ostream& o)
	{
		o << (B*) this;
		o << parameter;
	}
}

main()
{
C myC( 20, 10, "aname');
cout << C;
}

this code only displays the parameter value. It do not call the other
operators << for some reason. Is There any thing wrong with the cast.

Friend functions are not inherited does this mean that I can not call
them through the this pointer using the cast?.

I am setting some of the fields using cout.setf( io::hex ) after I use
the cast I do not think this has any effect in the problem.

Does it make sense to make a private method virtual, it can not be
called from the derived functions



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