Answer / raj

In multiple inheritance when a class D is derived by two
base classes B and C and both base class is also inherite
by same class A then then class D will get duplicate copy
of uppper most base class A.In this case class A will
declare as virtual class

Answer / kar4you

Suppose you have two derived classes B and C that have a
common base class A, and you also have another class D that
inherits from B and C. You can declare the base class A as
virtual to ensure that B and C share the same subobject of
A.

In the following example, an object of class D has two
distinct subobjects of class L, one through class B1 and
another through class B2. You can use the keyword virtual
in front of the base class specifiers in the base lists of
classes B1 and B2 to indicate that only one subobject of
type L, shared by class B1 and class B2, exists.

class L { /* ... */ }; // indirect base class
class B1 : virtual public L { /* ... */ };
class B2 : virtual public L { /* ... */ };
class D : public B1, public B2 { /* ... */ }; // valid

Answer / ramakrishna

It is used to avoid the ambiguity problem in c++ (multiple
inheritance).
when sub class inherits same members from 2 base classes.
compiler dont know which variable has assigned the value.

If u declare the class as virtual only one time is
inherited in its derived class.A copy will never get
inherited.
concept of virtual methods is different purpose.
like how we have abstract key word in java,we can acheive
method abstraction using virtual keyword before a method.

please select no if u really know this answer is wrong.
people with out having knowlede saying simple know hurts
the technical world.
Regards,
Ramakrishna Yechuri
sr corporate Trainer
yrk_in@yahoo.com

Answer / ritesh parkhi

Virtual class in a part or used to implement Runtime
polymorphism.Through it dynamically we can access a class or
method of that class.With use of Pointer to base class we
can implememt it.We try to access object of any class
without regarding their class.We are passing object address
in this base class pointer to access a particulat method of
a class at runtime.

Answer / roll no 009

it is nuthin but a class which consists of 72 students wid
a borin h.o.d who thinks all are listening but you know the
truth i.e no 1 is 4 sure..such a type of class is called
a "VIRTUAL CLASS"..

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