What is .cs?

.cs files contain source code written in C# (pronounced 'C Sharp'), a modern, object-oriented, and type-safe programming language developed by Microsoft. It runs on the .NET framework and is widely used for building Windows applications, web services, and video games.

This quick guide explains when to use .cs files, how to open them on any device, and how to share them instantly with FileXhost.

When to use .cs files

You are developing video games using the Unity engine.
You are building enterprise web applications with ASP.NET Core.
You are creating Windows desktop applications (WPF, WinForms).
You want a powerful, strongly-typed language with modern features.

How to open .cs files

CS files are plain text and can be edited in any text editor. However, for actual development, Visual Studio or VS Code (with the C# Dev Kit) are the standard tools.

Algorithm details

C# is a compiled language, but it compiles to an Intermediate Language (IL) rather than direct machine code. The Common Language Runtime (CLR) then executes this IL, handling memory management (Garbage Collection) and security.

Browser & platform support

Direct: Not supported by browsers.
WebAssembly: Blazor (a .NET framework) allows C# to run directly in the browser via WebAssembly.

Format comparison

Feature	Details
Versatility	Can build almost anything: web, mobile (Xamarin/MAUI), desktop, cloud, and games.
Safety	Type-safe and memory-safe (automatic garbage collection), preventing many common bugs found in C++.
Ecosystem	Backed by Microsoft with massive support, documentation, and the powerful .NET ecosystem.

How to create cs files

IDEs: Visual Studio (New > Class).
Unity: Right-click > Create > C# Script.
CLI: 'dotnet new console' creates a project with Program.cs.

How to convert cs files

Compiler: 'csc Program.cs' or 'dotnet build' creates an executable (.exe or .dll).
FileXhost: Upload to share source code.

Advantages & disadvantages

Advantages

Excellent developer tooling (Visual Studio is top-tier)
Standard language for game development (Unity)
Cross-platform (runs on Windows, Mac, Linux via .NET Core)
Rich standard library

Disadvantages

Heavier runtime than C/C++
Historically Windows-centric (though this has changed with .NET Core)
Garbage collection pauses can affect real-time performance (in extreme cases)

Tools & software

IDEs

Visual Studio (Recommended), JetBrains Rider, VS Code

Game Engines

Unity, Godot (C# version)

Frameworks

.NET, ASP.NET Core, Blazor, Xamarin/MAUI

Frequently asked questions

Why is it called C#?

It's inspired by musical notation, where a 'sharp' symbol indicates that a note is higher in pitch. It's metaphorically 'C++' incremented (++).

Can I run C# on a Mac?

Yes! With modern .NET (formerly .NET Core), C# is fully cross-platform and runs great on macOS and Linux.

Is C# harder than Python?

Generally, yes. It has a steeper learning curve due to being statically typed and having more verbose syntax, but the tooling helps a lot.

Technical specs

File type: Code
Extension: .cs
MIME type: text/x-csharp, text/plain
Compression: Uncompressed
Max file size on FileXhost: Up to 25 MB per file on the free plan and up to 1 GB on Pro FileXhost accounts.

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