What Is C#?
C# (pronounced "C sharp") is a general-purpose, multi-paradigm programming language created by Microsoft and first released in 2000 as part of the .NET initiative. It combines the performance and low-level control associated with C and C++ with the productivity and safety of managed, garbage-collected languages like Java. C# is statically typed, strongly typed, and compiled to an intermediate language (IL) that runs on the .NET runtime (CLR), which means the same C# code can run on Windows, Linux, and macOS. Over more than two decades, C# has evolved from a Windows-centric, Java-like language into one of the most versatile languages in the industry, used to build web APIs, desktop apps, mobile apps, games, cloud services, and machine-learning pipelines.
Cricket analogy: Like a modern all-format player who blends the raw power of T20 with the disciplined technique of Test cricket, C# blends low-level control from C/C++ with the safety of managed languages, and plays on every ground worldwide.
Origins and Design Philosophy
C# was designed by Anders Hejlsberg (previously the architect of Turbo Pascal and Delphi) as Microsoft's answer to Java, but with the explicit goal of being a modern, component-oriented language from day one — with first-class support for properties, events, and versioning built into the language rather than bolted on as conventions. The language was standardized by ECMA and ISO, meaning its specification is open and not solely controlled by Microsoft. Since 2014, C# and the .NET runtime have been open source under the .NET Foundation, and development happens transparently on GitHub with a public language-design process.
Cricket analogy: Just as a cricket board publishes an official, publicly reviewable rulebook rather than one federation's private house rules, C# was standardized by ECMA and ISO, its specification openly reviewable rather than Microsoft's alone.
Where C# Runs Today
Modern C# code targets .NET (formerly .NET Core), a free, open-source, cross-platform runtime maintained by Microsoft and the community. A single C# codebase can be compiled to run on Windows, Linux, and macOS, deployed as a cloud-native container, compiled ahead-of-time to a native binary, or even transpiled to run inside a web browser via Blazor WebAssembly. This is a significant departure from the early 2000s, when C# was tied almost exclusively to the Windows-only .NET Framework.
Cricket analogy: A modern all-rounder who can adapt their game to any pitch, whether a dusty subcontinental wicket or a green seaming English one, mirrors how modern C# code targets .NET and runs unmodified across Windows, Linux, and macOS.
// A minimal, modern C# program using top-level statements (C# 9+)
// No explicit Main method, no explicit class wrapper required.
Console.WriteLine("C# is a statically typed, object-oriented language for .NET.");
var version = Environment.Version;
Console.WriteLine($"Running on .NET runtime version: {version}");
// C# supports multiple paradigms: OOP, functional-style LINQ, and more.
var languages = new[] { "C#", "F#", "VB.NET" };
var managedLanguages = languages.Where(l => l != "VB.NET").ToList();
Console.WriteLine(string.Join(", ", managedLanguages));Unlike Java, which compiles to JVM bytecode, C# compiles to Common Intermediate Language (CIL) that runs on the Common Language Runtime (CLR). Both are JIT-compiled managed platforms, but .NET additionally supports multiple source languages (C#, F#, VB.NET) sharing the same runtime and standard library via the Common Type System.
A common misconception is that C# only runs on Windows. Since the .NET Core rewrite (2016 onward, unified as just ".NET" from .NET 5), C# is fully cross-platform, and most new C# development — including ASP.NET Core web APIs — targets Linux containers in production.
- C# is a statically typed, object-oriented, component-based language created by Microsoft, first released in 2000.
- It compiles to Intermediate Language (IL) executed by the Common Language Runtime (CLR), enabling cross-language interop within .NET.
- C# and .NET have been open source and cross-platform (Windows, Linux, macOS) since .NET Core launched in 2016.
- The language is standardized by ECMA/ISO, so its specification is not solely proprietary to Microsoft.
- C# is used across web (ASP.NET Core), desktop (WPF/MAUI), mobile (MAUI), games (Unity), and cloud services.
- Anders Hejlsberg designed C# with built-in support for properties, events, and delegates as first-class language features.
Practice what you learned
1. What does C# compile to before it is executed by the .NET runtime?
2. Who is credited as the original chief architect of C#?
3. Since which major shift has C# been reliably cross-platform (Windows, Linux, macOS)?
4. Which organizations have standardized the C# language specification?
5. Which of these is NOT a typical use case for modern C#?
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