Always instantiate the abstract class due to the following members:
What is this??

CodePudding user response:

Don't post code, didn't also give error messages, online search, you should be able to find the answer on your own, online reference answer:

The reason for the error:
An implementation class inherits an abstract base class, but not all of the abstract base class method,

CodePudding user response:

An abstract class cannot be directly instantiated, the subclass to instantiate