4 ms·

Two obvious differences off the top of my head: 1. Overriden methods have access to the internal state of the parent class, which is almost universally a bad i

• wvenable 8y ago
  #1 isn't true; you only have access to the state that subclasses are allowed to have (assuming you're using a language with any protection at all). #2 is a good point. But there are some limitations as well. You don't get to augment the default implementation unless it is also exposed somewhere (passed into the function). Both methods have a lot in common with the obvious differences that you mention. A class with no public methods and a empty virtual function is equivalent to a class calling a higher order function in the same place. If that virtual function has a implementation, you can get the same functionality with a higher order function by passing in the base implementation as a parameter. For full equivalence, you could also pass the object instance as well. Add in protected methods and/or state and you can get that with a second class that implements an internal API and again pass that to the higher-order function. Ultimately you can achieve all kinds of equivalence this way. I think there is some advantage to using the terminology in the language (private, protected, virtual, abstract, this/base, etc) to describe the more complex situations. Having a simple function call is useful for more simple situations. This is the classic struggle.