What is the difference between an abstract function and a virtual function in c#?

Abstract function:

An abstract function cannot have functionality. You’re basically saying, any child class MUST give their own version of this method, however, it’s too general to even try to implement in the parent class.

Virtual function:

A virtual function is basically saying look, here’s the functionality that may or may not be good enough for the child class. So if it is good enough, use this method, if not, then override me, and provide your own functionality.