Differences between interfaces and abstract classes

Abstract classes are similar to interfaces, but they have different ideas. An interface is a member of a public class, while an abstract class is a member of an abstract class to require subclass inheritance and implementation.

Abstract class: abstract class is an abstraction of commonalities.

1. Unlike normal classes, abstract classes must be modified using abstract.
2. If a class contains abstract methods, the class must be abstracted (declared as an abstract class and not implemented ).
3. The subclass that inherits the abstract class must override the abstract method of the parent class.
4. Abstract classes cannot be instantiated.
5. Abstract classes can be used for polymorphism.
6. It can contain abstract methods and non-abstract methods.
7. Members can use static, abstract, override, and virtual modifiers.

　　Define abstract classes and abstract methods:

abstract  class CashSuper{   public abstract double acceptCash(double money);}　

Abstract methods using abstract classes:

class CashNormal : CashSuper{　　public override double acceptCash(double money)   {   　　return money;   }}

Interface: an interface is an abstraction of behavior.

1. Any non-Abstract type that implements an interface must implement all the members of the interface.
2. The interface cannot be instantiated.
3. Interfaces can contain events, indexers, methods, and attributes.
4. Classes and structures can inherit multiple interfaces.
5. The interface itself can be inherited from multiple interfaces.
6. Methods can only be abstract methods.
7. All members are public static final and cannot use static, abstract, override, or virtual modifiers.

Example:

interface MyInterface     {               string ID        {            set;            get;        }        string Name         {            set;            get;        }        void ShowInfo();    }

 

Differences between interfaces and abstract classes