C# – Introduction

C# is a modern, strongly-typed language that runs on the .NET runtime (CLR) and is built with the .NET SDK. It powers web APIs (ASP.NET Core), cloud services (Azure/AWS/GCP), desktop (WinUI/WPF), mobile (MAUI/Xamarin), games (Unity), and AI workloads.

Why it’s relevant

Performance features (SPAN, AOT), safety (nullable refs), productivity (records, pattern matching)
First-class tooling (Visual Studio, VS Code, analyzers, source generators)
Regular evolution cadence (C# 1.0 → latest preview)

Tiny sample (top-level statements; C# 9+)

using System;

Console.WriteLine("Hello, C#");

How to read this section

Versions → a timeline from C# 1.0 to the latest
Features → a single index of all features with version/status
Groups → curated overviews that cluster related features
Feature details → deep-dive pages with before/after and best practices