C # Fourth Day

Object oriented

OPP: Object-oriented

Class members include: Methods, properties, struct

Class: Divided into two major categories

1. Abstract classes cannot be instantiated, only methods can be overridden in an inherited subclass

2. Sealed class (SEATD) can only be used in the class in which it is currently located

A subclass inherits only one parent class, but can inherit multiple interfaces

Interfaces: Methods defined with the interface keyword

Inheritance: Defines a function or method: The inherited class or the name of the inherited interface

Multiple inheritance is separated by commas

All base classes: System.Object

In one method, if there are more than one function, the constructor is first performed

Constructors: Function names and method names are the same

There is only one constructor in each class, and the default is a non-parametric, non-return constructor

To define a virtual method:

Modifier virtual return value Method name ()

｛

Method content

｝

Override: Modifier override return value method name ()

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What is implemented

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C # Fourth Day