Do virtual functions need to be public?

Do virtual functions need to be public?

Virtual functions, in their view, should never be public, because they define the class’ interface, which must remain consistent in all derived classes. Protected and private virtuals define the class’ customizable behavior, and there is no need to make them public.

When should a function be virtual?

So when should I declare a destructor virtual? Whenever the class has at least one virtual function. Having virtual functions indicate that a class is meant to act as an interface to derived classes, and when it is, an object of a derived class may be destroyed through a pointer to the base.

What are the rules for declaring virtual functions?

Rules for Virtual Functions

• Virtual functions cannot be static.
• A virtual function can be a friend function of another class.
• Virtual functions should be accessed using pointer or reference of base class type to achieve run time polymorphism.

Where the virtual function should be declared?

5. Where the virtual function should be defined? Explanation: The virtual function should be declared in base class. So that when the derived class inherits from the base class, the functions can be differentiated from the one in base class and another in derived class.

Can you override private virtual methods?

You can’t declare private virtual methods because there’s no point (since there’d be no way to override them)… But you can override protected virtual methods.

What is the rule of virtual function?

Rules of Virtual Function Virtual functions must be members of some class. Virtual functions cannot be static members. They are accessed through object pointers. They can be a friend of another class. A virtual function must be defined in the base class, even though it is not used.

Can virtual function be inlined C++?

13 Answers. Virtual functions can be inlined sometimes. An excerpt from the excellent C++ faq: “The only time an inline virtual call can be inlined is when the compiler knows the “exact class” of the object which is the target of the virtual function call.

What is virtual destructor in C++ with example?

Deleting a derived class object using a pointer of base class type that has a non-virtual destructor results in undefined behavior. To correct this situation, the base class should be defined with a virtual destructor. For example, following program results in undefined behavior.

Why do you need a virtual function in MSDN?

Virtual functions ensure that the correct function is called for an object, regardless of the expression used to make the function call. Suppose a base class contains a function declared as virtual and a derived class defines the same function.

How is a virtual function declared in C + +?

A virtual function is a special form of member function that is declared within a base class and redefined by a derived class. The keyword virtual is used to create a virtual function, precede the function’s declaration in the base class.

Can a virtual function be a friend function?

Virtual functions cannot be static and also cannot be a friend function of another class. Virtual functions should be accessed using pointer or reference of base class type to achieve run time polymorphism. The prototype of virtual functions should be same in base as well as derived class.

When to use virtual functions in derived classes?

c. v. m. M. m. In this article. 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.