Multiple Classes in a Single Source File

C# Tutorials - Herong's Tutorial Examples

∟Multiple Classes in a Single Source File

This section provides a tutorial example on how to write multiple classes in a single C# source code file.

Unlike Java, C# allows you to write multiple classes in a single source file.

Here is a tutorial example C# source file that contains 2 classes, UtilTest.cs:

// UtilTest.cs
// Copyright (c) 2010 HerongYang.com. All Rights Reserved.

using System;
public class UtilTest {
   public static void Main() {
      string a = "blue";
      string b = "sky";
      Console.WriteLine("{0} {1}", a, b);
      Util.Swap(ref a, ref b);
      Console.WriteLine("{0} {1}", a, b);
   }
}
public class Util {
   public static void Swap(ref string x, ref string y) {
      string o = x;
      x = y;
      y = o;
   }
}

Note that:

The "Util" class has only a single static method "Swap()". May be I will add more methods later.
The "UtilTest" class has a program execution entry method "Main()". It is used to test the "Swap()" defined in the "Util" class.
Remember only execution entry method "Main()" is allowed in a single source file.

If you compile and run this source file, you will get:

C:\herong>\Windows\Microsoft.NET\Framework\v4.0.30319\csc UtilTest.cs

C:\herong>UtilTest.exe
blue sky
sky blue

Table of Contents

About This Book

Introduction of C# (C Sharp)

Data Type and Variables

Logical Expressions and Conditional Statements

Arrays and Loop Statements

Data Type Features

Floating-Point Data Types

Passing Parameters to Methods

Execution Environment Class

Visual C# 2010 Express Edition

Class Features

C# Compiler and Intermediate Language

►Compiling C# Source Code Files

C# Compiler "csc" Options

►Multiple Classes in a Single Source File

Compiling Multiple Source Code Files Together

Generating and Using .NET Library Files

MSBuild - Microsoft Build Engine

Memory Usages of Processes

Multithreading in C#

Async Feature from C# 5

System.IO.FileInfo Class

System.Diagnostics.FileVersionInfo Class

WPF - Windows Presentation Foundation

Partial Classes and Partial Methods

Archived Tutorials

References

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