Programming in the Key of C#: A Primer for Aspiring Programming

C# is not the only programming language you can use for .NET programming. Microsoft published a Common Language Specification (CLS) that defines a minimum standard of features that a programming language must have to use .NET. It is expected that many programming languages will be adapted in accordance with the CLS. But C# is the programming language designed specifically for .NET and the language that has the closest fit with the features of .NET.

As the name of the language suggests, C# is a descendent of sorts of the C and C++ programming languages, and it also bears some similarity with Java, a language that was also influenced by C and C++. These C-family languages (as they’re now called) all have similar syntax, but the differences deepen on closer inspection. In particular, C# is part of a trend toward the use of programming languages that sacrifice a little efficiency in favor of safety. As I’ll discuss in the first chapter, C and C++ became popular partially because programs written in these languages are often fast and use a minimum amount of memory. These languages achieve this efficiency by assuming that the programmer is very smart and doesn’t make mistakes; the languages themselves don’t provide any checks to determine if the program is doing anything wrong, such as accessing memory it shouldn’t be accessing. C and C++ programs may be fast, but they can often have bugs that are difficult to diagnose.

Nowadays, machines are fast enough and memory is cheap enough that program efficiency is not a primary concern. What we care about more than efficiency is that programs be as free from bugs as possible. While no programming language lets programmers write entirely bug-free programs, C# goes a long way in comparison with C and C++. For that reason, C# programs are safer to run.

C# programs are also safer in another respect. As programs are transferred over the Internet, users need to be assured that the programs won’t damage their computers or data in some way. C# (like Java) helps out here as well. Traditionally, the primary tool a programmer uses is a compiler that converts the program source code (what the programmer writes) into an executable (which the computer runs). In contrast, the C# compiler converts program source code into a file that contains intermediate language (IL), which cannot be directly executed on a computer. Before the program is actually run, the IL can be examined to determine whether it’s capable of doing anything bad. The IL is then converted into an executable file. This latter process is the province of the .NET common language runtime (CLR).

As I began working with C# in 2000, it quickly became my preferred programming language. C# duplicates much of the concise syntax of C that I’ve enjoyed since first learning C in 1985. But C# also adds modern, object-oriented features while retaining very little unnecessary baggage from C. The language has combined the old and the new in an almost perfect balance.

Soon after I began working with C#, I also realized that it qualifies as a good first programming language for new programmers. C# is elegant and powerful, and it often protects the new programmer against common errors. Hence, I decided to write this book.

I mentioned earlier that you use C# to write .NET Web or Windows-based applications. But these are really user interface options, and that’s not what this book is about. This book is about the C# programming language itself. Consequently, I’ve tried to write this book so that you can focus entirely on C# without distractions. What you later decide to use C# for is up to you. Still, programs need some way to communicate with the outside world. For this book, I’ve chosen to use a type of user interface known as the console. The advantage of the console is that it’s simple, and what you learn is applicable to any type of programming you’ll eventually do. If you’d like to write Windows-based applications after you’ve finished this book, for example, you can jump right into Chapter 2 of my book Programming Microsoft Windows with C# (Microsoft Press, 2001).

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