C# 0 The Complete Reference

/*

 and end with 

*/

. Anything 

between these two comment symbols is ignored by the compiler. As the name suggests, a 

multiline comment can be several lines long.

The next line in the program is

using System;

This line indicates that the program is using the 

System

 namespace. In C#, a 

namespace

defines a declarative region. Although we will examine namespaces in detail later in this 

book, a brief description is useful now. Through the use of namespaces, it is possible to keep 

one set of names separate from another. In essence, names declared in one namespace will 

not conflict with names declared in a different namespace. The namespace used by the 

program is 

System

, which is the namespace reserved for items associated with the .NET 

Framework class library, which is the library used by C#. The 

using

 keyword simply states 

that the program is using the names in the given namespace.

The next line of code in the program is shown here:

class Example {

This line uses the keyword