What Is Virtual Void In C++?

What is virtual base class with example?

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 the use of virtual function in C++?

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.

What is virtual function explain with example?

– A virtual function is a member function that is declared within a base class and redefined by a derived class. When a class containing virtual function is inherited, the derived class redefines the virtual function to suit its own needs. … – Base class pointer can point to derived class object.

What is a pure virtual method C++?

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. Classes containing pure virtual methods are termed “abstract” and they cannot be instantiated directly.

Why do we need virtual function?

Virtual functions ensure that the correct function is called for an object, regardless of the type of reference (or pointer) used for function call. Functions are declared with a virtual keyword in base class. The resolving of function call is done at Run-time.

What is difference between virtual and pure virtual function?

A virtual function is a member function of base class which can be redefined by derived class. A pure virtual function is a member function of base class whose only declaration is provided in base class and should be defined in derived class otherwise derived class also becomes abstract.

Is a pure virtual function C++?

A pure virtual function is a virtual function in C++ for which we need not to write any function definition and only we have to declare it. It is declared by assigning 0 in the declaration. … If an Abstract Class has derived class, they must implement all pure virtual functions, or else they will become Abstract too.

Can pure virtual function have body C++?

Pure virtual (abstract) functions and abstract base classes So far, all of the virtual functions we have written have a body (a definition). However, C++ allows you to create a special kind of virtual function called a pure virtual function (or abstract function) that has no body at all!

What is virtual inheritance in C++?

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 is the advantage of virtual function in C++?

The main advantage of virtual functions are that they directly support object oriented programming. When you declare a function as virtual you’re saying that exactly what code is executed depends on the type of the object you call it against. you can’t tell exactly what code path it’s going to follow.

Are virtual functions inherited?

Base classes can’t inherit what the child has (such as a new function or variable). Virtual functions are simply functions that can be overridden by the child class if the that child class changes the implementation of the virtual function so that the base virtual function isn’t called.