What is the difference between virtual function and function overriding?

Answer 1

Virtual Functions and Pure Virtual Functions are relevant in the context of class inheritance.

Unlike Virtual Functions, Pure Virtual Functions do not require a body. This implies that when a base class defining such a function is inherited, the derived class must implement that function. Furthermore, the base class becomes abstract; meaning you cannot create an instance of the base class even if a body is implemented for the function. You are expected to derive from abstract classes; only the derived classes that implement all the inherited Pure Virtual functions can be instantiated.

Here are some examples of Virtual and Pure Virtual function signatures:

- Virtual Function: E.g. virtual void myFunction();

- Pure Virtual Function: E.g. virtual void myFunction() = 0;

Answer 2

In C#, a virtual function (defined in a base class) may be overridden by its derived class(es)

a virtual function provides a default implementation, the override is to change the behavior. It is not the same as "modifying the existing codes". The default one co-exist with the overrides, and may be called/invoked still!!

Answer 3

An overloaded function is any function that has two or more versions with different signatures but with the exact same name within the same namespace.

A virtual function is any class method that is declared virtual and is therefore expected to be overridden by derived classes.