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)

The HashSet<T> collection

A set is a collection that contains only distinct items that can be in any order. .NET provides the HashSet<T> class for working with sets. This class contains methods to handle the elements of the set but also methods to model mathematical set operations such as union or intersection.

Like all the other collections, HashSet<T> contains several overloaded constructors that allow us to create either an empty set or a set filled with initial values. To declare an empty set, we use the default constructor (which is the constructor without parameters):

HashSet<int> numbers = new HashSet<int>();

But we can also initialize the set with some values, as shown in the following example:

HashSet<int> numbers = new HashSet<int>()
    1, 1, 2, 3, 5, 8, 11

To work with a set, we can use the following methods:

  • Add() adds a new element to the set if the element is not already present...