What is a polymorphic class C++?

A class that declares or inherits a virtual function is called a polymorphic class. Note that despite of the virtuality of one of its members, Polygon was a regular class, of which even an object was instantiated ( poly ), with its own definition of member area that always returns 0.

Is virtual function a polymorphism?

A virtual function is a special type of function that, when called, resolves to the most-derived version of the function that exists between the base and derived class. This capability is known as polymorphism.

What kind of polymorphism is used with virtual functions?

The classes that have virtual functions are called polymorphic classes. The compiler binds virtual function at runtime, hence called runtime polymorphism. Use of virtual function allows the program to decide at runtime which function is to be called based on the type of the object pointed by the pointer.

What is polymorphism explain virtual function with example?

Polymorphism is the ability for objects of different classes related by inheritance to respond differently to the same member function call. In order to accomplish “run-time”, “late”, or “dynamic” binding we must use virtual functions. …

What is virtual function C++?

A virtual function is a member function which is declared within a base class and is re-defined(Overriden) by a derived class. Virtual functions ensure that the correct function is called for an object, regardless of the type of reference (or pointer) used for function call.

What are virtual classes 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. Need for Virtual Base Classes: Consider the situation where we have one class A .

Can you call a virtual function?

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.

What are virtual functions write an example?

Virtual Function in C++

• Virtual functions ensure that the correct function is called for an object, regardless of the type of reference (or pointer) used for function call.
• They are mainly used to achieve Runtime polymorphism.
• Functions are declared with a virtual keyword in base class.

What is the advantage of virtual function in C++?

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.

Can be declared as a virtual in a class?

Virtual Function in C++ A virtual function is a member function which is declared within a base class and is re-defined(Overriden) by a derived class. Functions are declared with a virtual keyword in base class. The resolving of function call is done at Run-time.

How can virtual function be used to implement the run time polymorphism?

The main use of virtual function is to achieve Runtime Polymorphism. Runtime polymorphism can be achieved only through a pointer (or reference) of base class type. Also, a base class pointer can point to the objects of base class as well as to the objects of derived class.

Is the member constant of a polymorphic class true?

If T is a polymorphic class (that is, a non-union class that declares or inherits at least one virtual function), provides the member constant value equal to true. For any other type, value is false . If T is a non-union class type, T shall be a complete type; otherwise, the behavior is undefined.

What is the definition of a polymorphic class?

A class that declares or inherits a virtual function is called a polymorphic class. Note that despite of the virtuality of one of its members, Polygon was a regular class, of which even an object was instantiated ( poly ), with its own definition of member area that always returns 0.

How is polymorphism achieved at runtime in C + +?

Runtime polymorphism can be achieved only through a pointer (or reference) of base class type. Also, a base class pointer can point to the objects of base class as well as to the objects of derived class. In above code, base class pointer ‘b’ contains the address of object ‘d’ of derived class.