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How do you call a virtual function through a base class reference?
When you refer to a derived class object using a pointer or a reference to the base class, you can call a virtual function for that object and execute the derived class’s version of the function.
Can a virtual function be implemented in a derived class?
Derived classes do not have to implement all virtual functions themselves. They only need to implement the pure ones. That means the Derived class in the question is correct.
How virtual functions are used in derived classes?
In C++, once a member function is declared as a virtual function in a base class, it becomes virtual in every class derived from that base class. In other words, it is not necessary to use the keyword virtual in the derived class while declaring redefined versions of the virtual base class function.
Can base class be declared as virtual?
When a base class is specified as a virtual base, it can act as an indirect base more than once without duplication of its data members. A single copy of its data members is shared by all the base classes that use virtual base. Explanation :The class A has just one data member a which is public.
How do I create a pure virtual function?
A pure virtual function is declared by assigning 0 in declaration.
Can a derived function be invoked from a virtual function?
Suppose a base class contains a function declared as virtual and a derived class defines the same function. The function from the derived class is invoked for objects of the derived class, even if it is called using a pointer or reference to the base class.
Can a derived class be invoked from a base class?
When you create a class that can be used as a base class for other classes, you should consider the fact that events are a special type of delegate that can only be invoked from within the class that declared them. Derived classes cannot directly invoke events that are declared within the base class.
How to call a function of a base class?
If you want to call a function of base class from its derived class you can simply call inside the overridden function with mentioning base class name (like Foo::printStuff () ).
When to use virtual function in base class?
If a class is declared that does not provide an overriding implementation of the PrintBalance function, the default implementation from the base class Account is used. Functions in derived classes override virtual functions in base classes only if their type is the same.