How do you call a virtual method of base class in C++?

When you want to call a specific base class’s version of a virtual function, just qualify it with the name of the class you are after, as I did in Example 8-16: p->Base::foo(); This will call the version of foo defined for Base , and not the one defined for whatever subclass of Base p points to.

What is a virtual base class in C++?

Virtual base classes are used in virtual inheritance in a way of preventing multiple “instances” of a given class appearing in an inheritance hierarchy when using multiple inheritances.

What is virtual method in CPP?

A C++ virtual function is a member function in the base class that you redefine in a derived class. It is declared using the virtual keyword. When the function is made virtual, C++ determines which function is to be invoked at the runtime based on the type of the object pointed by the base class pointer.

How do you call a virtual function through a base class reference?

A virtual function is a member function that you expect to be redefined in derived classes. 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.

How are virtual base classes used in C + +?

Now only one copy of data/function member will be copied to class C and class B and class A becomes the virtual base class. Virtual base classes offer a way to save space and avoid ambiguities in class hierarchies that use multiple inheritances.

When is a pure virtual method required in C + +?

whereas.. A pure virtual function or pure virtual method is a virtual function that is required to be implemented by a derived class if the derived class is not abstract. When a pure virtual method exists, the class is “abstract” and can not be instantiated on its own. Instead, a derived class that implements the pure-virtual method (s)

How to create a virtual function in C + +?

1 Virtual functions cannot be static. 2 A virtual function can be a friend function of another class. 3 Virtual functions should be accessed using pointer or reference of base class type to achieve run time polymorphism. 4 The prototype of virtual functions should be the same in the base as well as derived class.

When is VF declared as virtual in a class base?

If some member function vf is declared as virtual in a class Base, and some class Derived, which is derived, directly or indirectly, from Base, has a declaration for member function with the same