How Virtual functions works in c++

refer below link:-
Understand Virtual functions Internals[^]
How Virtual Table and Virtual Table works in C++[^]

See for instance this Wikipedia page: "Virtual method table"[^].

Quote:

how to create a virtual function and what is use of it

One usage is to create abstract classes for example:

class Employee
{
...
virtual void getSalary() = 0; // by doing this you're creating an abstract class which means you can only inherit from it and can't create an object of it.
...
};

Another usage, suppose you have two classes Parent and Child. The Child class inherits from Parent class and Parent class has its own display function which will display for example "I'm parent", and the Child class has an overridden function display which will display for example "I'm child".
And you've this function:

void mFunction(Parent &p)
{
    p.display();
}

If you don't use virtual keyword for display function (virtual void display();) in parent's class then no matter what you pass Parent class object or Child class object it will display "I'm parent".

If you use virtual keyword
then it will display "I'm parent" if it is a Parent class object
or it will display "I'm child" if it is a child class object.

There might be other usages that I don't know about and I hope someone will help you with that.
Good luck.

Regards,
Mohammed Abdulgaffar.