answer?

[il_santo]

class X { class Y : class X {
protected: public:
int a; void g();
public: int k;
int c; };
private:
int b;
public:
void f();
};

An object of Y could access the var:
a) a,b,c
b)a,b
c)only c
d)only a
e)a,c
f)c,b
g)I don't know
This is exercise was in a test of C++ and i'm not rreally sure what to
choose. Could you give me an answer and tell me the relationship betwen
dhe public, private and protected of the variables in the derived
class? I supose that you have understand that I'm a begginer.

[Risto Lankinen]

"il_santo" <al*******@yahoo.com> wrote in message
news:11*********************@g43g2000cwa.googlegro ups.com...

class X { class Y : class X {
protected: public:
int a; void g();
public: int k;
int c; };
private:
int b;
public:
void f();
};

An object of Y could access the var:
a) a,b,c
b)a,b
c)only c
d)only a
e)a,c
f)c,b
g)I don't know
This is exercise was in a test of C++ and i'm not rreally sure what to
choose. Could you give me an answer and tell me the relationship betwen
dhe public, private and protected of the variables in the derived
class? I supose that you have understand that I'm a begginer.

For you, the correct answer is clearly "g)"...

[Grahamo]

Hi,

first off be careful sending mails like that to the group. There are
individuals that respond in a not-so-polite manner sometimes. I'd
always try to at least have a stab at an answer before posting, perhaps
including your reasoning. That way you'll get the most from the
newsgroup and will find results the quickests.
So if I were you, I'd take a first look at what it the access modifiers
public, private and protected mean. What do you think they mean? i.e.
what's the difference between public and private? public and protected?
Or maybe put another way, if you didn't want a variable to be
accessible in a derived/subclass, how would you declare it?

Also. if you wanted a variable to be available only within the class in
which it is defined and derived/subclasses, how would you declare it?

therein lies the answer to your question... :)

Cheers

GrahamO

[Manfred]

il_santo wrote:

class X { class Y : class X {
protected: public:
int a; void g();
public: int k;
int c; };
private:
int b;
public:
void f();
};

An object of Y could access the var:
a) a,b,c
b)a,b
c)only c
d)only a
e)a,c
f)c,b
g)I don't know
This is exercise was in a test of C++ and i'm not rreally sure what to
choose. Could you give me an answer and tell me the relationship betwen
dhe public, private and protected of the variables in the derived
class? I supose that you have understand that I'm a begginer.

Hi

maybe you should have a look at:

http://www.parashift.com/c++-faq-lit...heritance.html

All other topics covered by the faq are
interesting too, especially if you are a beginner
like you told.

Manfred

[John Harrison]

il_santo wrote:

class X { class Y : class X {
protected: public:
int a; void g();
public: int k;
int c; };
private:
int b;
public:
void f();
};

An object of Y could access the var:
a) a,b,c
b)a,b
c)only c
d)only a
e)a,c
f)c,b
g)I don't know
This is exercise was in a test of C++ and i'm not rreally sure what to
choose. Could you give me an answer and tell me the relationship betwen
dhe public, private and protected of the variables in the derived
class? I supose that you have understand that I'm a begginer.

There is no correct answer to the question (except maybe g). I would
guess that the person who asked this question doesn't understand
protected access. Because access to var 'a' does not depend only on
which class is making the access, it also depends on how the access is
made. So as the question is posed it cannot be answered.

john

[Old Wolf]

John Harrison wrote:

il_santo wrote:

class X { class Y : class X {
protected: public:
int a; void g();
public: int k;
int c; };
private:
int b;
public:
void f();
};

An object of Y could access the var:
a) a,b,c
b)a,b
c)only c
d)only a
e)a,c
f)c,b
g)I don't know

There is no correct answer to the question (except maybe g). I
would guess that the person who asked this question doesn't
understand protected access.

I would say the answer is 'only c'. The example uses private
derivation, so the private and protected members of the base
class are not accessible by the derived class.
Because access to var 'a' does not depend only on
which class is making the access, it also depends on how the
access is made.

Supposing the derivation were public, when does it depend
on how the access is made? Member functions of an instance
of class Y (which is what I presume the OP is referring to)
can access the protected variables of class X.

[Alf P. Steinbach]

* Old Wolf:

John Harrison wrote:

il_santo wrote:

class X { class Y : class X {
protected: public:
int a; void g();
public: int k;
int c; };
private:
int b;
public:
void f();
};

An object of Y could access the var:
a) a,b,c
b)a,b
c)only c
d)only a
e)a,c
f)c,b
g)I don't know

There is no correct answer to the question (except maybe g). I
would guess that the person who asked this question doesn't
understand protected access.

I would say the answer is 'only c'. The example uses private
derivation, so the private and protected members of the base
class are not accessible by the derived class.

A C cast casts away that inaccessability, in a standard-conforming way, and
the operative word is "could"... ;-)

Furthermore, since nothing about portability and standard conformance is
mentioned, I wouldn't have any problems accessing the 'b' variable.

What do you bet a _correct_ answer (except g) wouldn't give full marks?

--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

[Alf P. Steinbach]

* Alf P. Steinbach:

[rubbish]

I've got the flu; disregard please.

--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?