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A virtual function allows derived classes to replace the implementation provided by the base class. The compiler makes sure the replacement is always called whenever the object in question is actually of the derived class, even if the object is accessed by a base pointer rather than a derived pointer.
Why virtual classes are important in the case of multiple inheritances?
Virtual inheritance is a C++ technique that ensures only one copy of a base class’s member variables are inherited by grandchild derived classes. This feature is most useful for multiple inheritance, as it makes the virtual base a common subobject for the deriving class and all classes that are derived from it.
What will not be achieved by using multiple inheritance?
So multiple inheritance is forbidden as bringing more problems than gains. Java supports multiple inheritance through interfaces only. A class can implement any number of interfaces but can extend only one class. Multiple inheritance is not supported because it leads to deadly diamond problem.
When to use multiple inheritance in C + +?
Multiple inheritance is a powerful and tricky tool to use in C++ programming language but sometimes it needs to be handled with care. Virtual inheritance is used when we are dealing with multiple inheritance but want to prevent multiple instances of same class appearing in inheritance hierarchy.
When to use virtual inheritance in multiple inheritance?
Virtual inheritance is used when we are dealing with multiple inheritance but want to prevent multiple instances of same class appearing in inheritance hierarchy. From above example we can see that “A” is inherited two times in D means an object of class “D” will contain two attributes of “a” (D::C::a and D::B::a).
How are base classes embedded in virtual inheritance?
As we can see clearly in virtual inheritance base class will not be embedded in derived class only a pointer will be provided which is pointing to the base class object but in non virtual inheritance we can see a base class embedded in derived class.
Can a virtual modifier be used to override a base method?
You cannot use the new, static, or virtual modifiers to modify an override method. The overridden base method must be virtual, abstract, or override. Meaning that you can override a method that is already marked as override. Is this answer outdated?