.cs File — C# Source Code
text/x-csharp
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text/x-csharpQuick Facts
| Extension | .cs |
| Full Name | C# Source Code |
| MIME Type | text/x-csharp |
| Category | Code |
| Type | Text-based (human-readable) |
| Typical Size | 1 KB – 100 KB |
| First Appeared | 2000 |
What Is a .cs File?
C# (C-sharp) is a modern, object-oriented programming language developed by Anders Hejlsberg at Microsoft, first released in 2000 as part of the .NET initiative. CS files contain source code in a statically-typed, garbage-collected language that combines the power of C++ with the productivity of higher-level languages. C# is the primary language for the .NET ecosystem, used for Windows desktop applications (WPF, WinForms, MAUI), web applications (ASP.NET Core), cloud services (Azure Functions), game development (Unity engine), mobile apps (Xamarin/MAUI), and enterprise backend systems. The language features classes, interfaces, generics, LINQ (Language Integrated Query), async/await for asynchronous programming, pattern matching, nullable reference types, records, and top-level statements. C# has evolved rapidly with annual releases adding modern features while maintaining backward compatibility. Unity, the world's most popular game engine, uses C# as its scripting language, making it essential for game developers. The .NET platform's cross-platform support (Windows, Linux, macOS) has expanded C#'s reach beyond its Windows-only origins.
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