Book Image

Learn C# Programming

By : Marius Bancila, Raffaele Rialdi, Ankit Sharma
5 (1)
Book Image

Learn C# Programming

5 (1)
By: Marius Bancila, Raffaele Rialdi, Ankit Sharma

Overview of this book

The C# programming language is often developers’ primary choice for creating a wide range of applications for desktop, cloud, and mobile. In nearly two decades of its existence, C# has evolved from a general-purpose, object-oriented language to a multi-paradigm language with impressive features. This book will take you through C# from the ground up in a step-by-step manner. You'll start with the building blocks of C#, which include basic data types, variables, strings, arrays, operators, control statements, and loops. Once comfortable with the basics, you'll then progress to learning object-oriented programming concepts such as classes and structures, objects, interfaces, and abstraction. Generics, functional programming, dynamic, and asynchronous programming are covered in detail. This book also takes you through regular expressions, reflection, memory management, pattern matching, exceptions, and many other advanced topics. As you advance, you'll explore the .NET Core 3 framework and learn how to use the dotnet command-line interface (CLI), consume NuGet packages, develop for Linux, and migrate apps built with .NET Framework. Finally, you'll understand how to run unit tests with the Microsoft unit testing frameworks available in Visual Studio. By the end of this book, you’ll be well-versed with the essentials of the C# language and be ready to start creating apps with it.
Table of Contents (20 chapters)

Polymorphism

The last core pillar of object-oriented programming is polymorphism. Polymorphism is a Greek word that stands for multiple forms. This is the ability to use one entity in multiple forms. There are two types of polymorphism:

  • Compile-time polymorphism: When we have methods with the same name but different numbers or types of parameters, which is called method overloading.
  • Run-time polymorphism: This has two different aspects:

    On one hand, Objects of derived classes can be seamlessly used as objects of base classes in arrays or other types of collections, method parameters, and other places.

    On the other hand, Classes can define virtual methods that can be overridden in derived classes. At runtime, the Common Language Runtime (CLR) will invoke the implementation of the virtual member corresponding to the runtime type of the object. An object's declared type and its runtime type differ when objects of derived classes are used in place of objects of base classes...