An interface in c#, is a contract between itself and any class that implements it.
In this Blog, you can learn ASP.NET WEB API CRUD Operations With ASP.NET MVC And Entity Framework.
C# Abstract classes are used to declare common characteristics of subclasses. An abstract method contains a method signature, but no method body.
It is used to display only necessary and essential features of an object to outside the world.
An HttpClient can be used to send requests and retrieve their responses.