Question on virtual inheritance..

[cyrusNew]

Hi,

sorry if it was already asked,

I have a following class diagram

A =? A
| |
B C
\ /
\ /
D

Now :

class B : virtual public A {}
class C : virtual public A {}
class D : public B, public C {}

Will class D have duplicated values from A in such scenerio? I think not.

now, what about this :

class B : public A {}
class C : public A {}
class D : virtual public B, virtual public C {}

is it equivalent to the previous code? I mean will class D have duplicated
variables from A?

 

[Victor Bazarov]

sorry if it was already asked,

I have a following class diagram

A =? A
| |
B C
\ /
\ /
D

Now :

class B : virtual public A {}
class C : virtual public A {}
class D : public B, public C {}

Will class D have duplicated values from A in such scenerio? I think not.

now, what about this :

class B : public A {}
class C : public A {}
class D : virtual public B, virtual public C {}

is it equivalent to the previous code?
No.

I mean will class D have duplicated
variables from A?

Yes.

V

 

[cyrusNew]

Yes.

V

thank you, just one more question, Iam thining of changing one class from
plain inheritance (like above class C) to virtual inheritance. Actually this
class C is used in many places in application (many classes inherit from C)
but needs virtual inheritance only with one class (class D), my question is
if this will reduce efficiency or maybe cause code bloat?

 

[Victor Bazarov]

[...] Iam thining of changing one class from
plain inheritance (like above class C) to virtual inheritance. Actually this
class C is used in many places in application (many classes inherit from C)
but needs virtual inheritance only with one class (class D), my question is
if this will reduce efficiency or maybe cause code bloat?

No. But if you notice anything like that, come back and we'll talk then.

V