Book Image

C# 7.1 and .NET Core 2.0 ??? Modern Cross-Platform Development - Third Edition

By : Mark J. Price
Book Image

C# 7.1 and .NET Core 2.0 ??? Modern Cross-Platform Development - Third Edition

By: Mark J. Price

Overview of this book

C# 7.1 and .NET Core 2.0 – Modern Cross-Platform Development, Third Edition, is a practical guide to creating powerful cross-platform applications with C# 7.1 and .NET Core 2.0. It gives readers of any experience level a solid foundation in C# and .NET. The first part of the book runs you through the basics of C#, as well as debugging functions and object-oriented programming, before taking a quick tour through the latest features of C# 7.1 such as default literals, tuples, inferred tuple names, pattern matching, out variables, and more. After quickly taking you through C# and how .NET works, this book dives into the .NET Standard 2.0 class libraries, covering topics such as packaging and deploying your own libraries, and using common libraries for working with collections, performance, monitoring, serialization, files, databases, and encryption. The final section of the book demonstrates the major types of application that you can build and deploy cross-device and cross-platform. In this section, you'll learn about websites, web applications, web services, Universal Windows Platform (UWP) apps, and mobile apps. By the end of the book, you'll be armed with all the knowledge you need to build modern, cross-platform applications using C# and .NET.
Table of Contents (31 chapters)
Title Page
Credits
About the Author
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface
2
Part 1 – C# 7.1
8
Part 2 – .NET Core 2.0 and .NET Standard 2.0
16
Part 3 – App Models
22
Summary
Index

Defining local functions


A language feature introduced in C# 7 is the ability to define a local function. Local functions are the method equivalent to local variables. In other words, they are methods that are only visible and callable from within the containing method in which they have been defined. In other languages, they are sometimes called nested or inner functions.

We will use a local function to implement a factorial calculation.

Add the following code to the Person class:

// method with a local function 
public static int Factorial(int number) 
{ 
   if (number < 0) 
   { 
      throw new ArgumentException( 
        $"{nameof(number)} cannot be less than zero."); 
   }
   return localFactorial(number);

   int localFactorial(int localNumber) 
   {
      if (localNumber < 1) return 1;
      return localNumber * localFactorial(localNumber - 1);
   }
}

Note

Local functions can be defined anywhere inside a method: the top, the bottom, or even somewhere in the middle!

In the Program...