C# 9.0 Pocket Reference

C# is a general-purpose, type-safe, primarily object-oriented programming language, the goal of which is programmer productivity. To this end, the language balances simplicity, expressiveness, and performance. C# 9 is designed to work with the Microsoft .NET 5 runtime (whereas C# 8 targets .NET Core 3, and C# 7 targets .NET Core 2 and Microsoft .NET Framework 4.6/4.7/4.8).

Note

The programs and code snippets in this book mirror those in Chapters 2 through 4 of C# 9.0 in a Nutshell and are all available as interactive samples in LINQPad. Working through these samples in conjunction with the book accelerates learning in that you can edit the samples and instantly see the results without needing to set up projects and solutions in Visual Studio.

To download the samples, click the Samples tab in LINQPad and then click “Download more samples.” LINQPad is free—go to www.linqpad.net.

A First C# Program

Following is a program that multiplies 12 by 30 and prints the result, 360, to the screen. The double forward slash indicates that the remainder of a line is a comment:

int x = 12 * 30;                  // Statement 1
System.Console.WriteLine (x);     // Statement 2

Our program consists of two statements. Statements in C# execute sequentially and are terminated by a semicolon. The first statement computes the expression 12 * 30 and stores the result in a variable, named x, whose type is a 32-bit integer (int). The second statement calls the WriteLine method on a class called Console ...