Sams Teach Yourself C in 21 Days

The C# Programming Language 771

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available. If you don’t have Visual Studio .NET, however, you can still do C#

programming.

There are also other editors available for C#. Like Visual Studio .NET, many of these

enable you to do all the steps of the development cycle without leaving the editor. More

importantly, most of these color-code the text you enter. This makes it much easier to

find possible mistakes. Many editors will even help you by given you information on

what you need to enter and giving you a robust help system.

If you don’t have a C# editor, don’t fret. Most computer systems include a program that

can be used as an editor. If you’re using Microsoft Windows, you can use either Notepad

or WordPad as your editor.

As you will learn later, unlike C, C++, and Java, a C# compiler is available free of

charge. Because of this, you can start programming C# programs without spending

any money!

Naming Your Source Files

Although not explicitly stated, you have seen that C programs tend to have a .c exten-

sion. C++ programs generally have a .cpp extension. Java programs have a .java exten-

sion. For your C# programs, you’ll want to include a .cs extension. Although you could

give your source file any name and extension, .cs is recognized as the appropriate

extension to use.

Executing a C# Program

It is important to understand a little bit about how a C# program executes. C# programs

are different from programs you could create with other programming languages.

C# programs are created to run on the Common Language Runtime (CLR). This means

that if you create a C# executable program and try to run it on a machine that doesn’t

have the CLR or a compatible runtime, it won’t execute.

The benefit of creating programs for a runtime environment is portability. In languages

such as C and C++, if you wanted to create a program that could run on different plat-

forms or operating systems, you had to compile different executable programs. For

example, if you wrote a C application and you wanted to run it on a Linux machine and

a Windows machine, you would have to create two executable programs—one on a

Linux machine and one on a Windows machine. With C#, you create only one executable

program, and it runs on either machine.

If you want your program to execute as fast as possible, you want to create a true

executable. With programs such as C and C++, the compiler creates a file that

can be executed with no further effort.

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