C# 0 The Complete Reference

A Small Variation

Although all of the programs in this book will use it, the line

using System;

at the start of the first example program is not technically needed. It is, however, a valuable 

convenience. The reason it’s not necessary is that in C# you can always 

fully qualify

 a name 

with the namespace to which it belongs. For example, the line

Console.WriteLine("A simple C# program.");

can be rewritten as

System.Console.WriteLine("A simple C# program.");

Thus, the first example could be recoded as shown here:

// This version does not include "using System;".

class Example {

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PART I

C h a p t e r   2 :  

A n   O v e r v i e w   o f   C #  

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PART IPART I

  // A C# program begins with a call to Main().

  static void Main() {

    // Here, Console.WriteLine is fully qualified.

    System.Console.WriteLine("A simple C# program.");

  }

}

Since it is quite tedious to always specify the 

System

 namespace whenever a member 

of that namespace is used, most C# programmers include 

using System

 at the top of their 

programs, as will all of the programs in this book. It is important to understand, however, 

that you can explicitly qualify a name with its namespace if needed.