Nine notes for abstract methods and nine Abstract METHODS

Nine notes for abstract methods and nine Abstract METHODS

1. abstract class keywords abstract

2. abstract classes cannot be instantiated.

3. the abstract method does not have a method body.

4. the shortcut key Ctrl +. + Enter for subclass to implement the abstract Method

5. If a class inherits the abstract class, rewrite all methods in the class.

7. abstract classes cannot be static or Sealed Classes

8. abstract class methods can only exist in abstract classes.

9. abstract methods in abstract classes are only used to specify the form (parameter, return value) of subclass methods to constrain subclass methods.