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)

Nullable reference types

In the previous chapter, we learned that the type system in C# is split into reference types and value types. Value types are allocated on the stack and subject to memory copies every time they are assigned to a new variable. On the other hand, reference types are allocated on the heap, which is managed by the garbage collector. Every time we allocate a new reference type, we receive a reference acting as a key to identify the allocated memory back from the garbage collector.

The reference is essentially a pointer that can assume the special null value, which is the simplest, and therefore most popular, way to indicate the absence of a value. Remember, instead of using the null value, another solution is to adopt the special case architectural pattern, which, in its simplest form, is an instance of that object with a Boolean field indicating whether the object is valid, which is how Nullable<T> works. In many other cases, developers don't really...