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)

Functions as first-class citizens

In Chapter 8, Advanced Topics, we learned about delegates and events. A delegate looks like a function but is a type that holds references to functions whose signatures match the definition of the delegate. Delegate instances can be passed as objects for function arguments. Let's look at an example where we have a delegate that takes two int parameters and returns an int value:

public delegate int Combine(int a, int b);

We then have different functions, such as Add(), which adds two integers and returns the sum, Sub(), which subtracts two integers and returns their difference, or Mul(), which multiplies two integers and returns their product. Their signature matches the delegate, so an instance of the Combine delegate can hold references to all these functions. These functions are shown as follows:

class Math
{
    public static int Add(int a, int b) { return a + b; }
    public static int Sub(int...