Introduction to C# and the .NET Ecosystem

What is C#?

C# is a modern, object-oriented programming language developed by Microsoft and widely used in professional software development. Introduced in 2000 alongside the .NET Framework, it has evolved into a fully cross-platform language with .NET 6/7/8, running on Windows, Linux, and macOS. Strong type safety, automatic memory management, rich standard libraries, and excellent IDE support make C# a popular choice for both individual developers and enterprise-level projects.

What is .NET?

.NET is not a programming language by itself, but a complete development platform and runtime environment that powers languages such as C#. Its core component, the Common Language Runtime (CLR), is responsible for executing managed code on the operating system in a secure and efficient way. Through the Base Class Library (BCL), .NET provides built-in functionality for file handling, collections, networking, and many other common programming tasks.

Historically:

• .NET Framework (2000): Worked only on Windows.
• .NET Core (2016): Became open-source and cross-platform.
• .NET 5+ (2020): Framework and Core were unified, now called simply “.NET”.

Why C#? What are its Advantages?

• Modern and safe: Thanks to type safety and strong language features, it is more resilient to errors.
• Object-oriented: Fully supports OOP features such as classes, interfaces, and inheritance.
• Cross-platform: Can run on Windows, Linux, and macOS with the same codebase.
• Large community: Easy to learn with rich documentation, forums like StackOverflow, and Microsoft support.
• Versatile use cases: Suitable for web, desktop, mobile, gaming, IoT, and cloud projects.

What Can Be Built with .NET?

• Web Applications: Modern websites and REST API services with ASP.NET Core.
• Desktop Applications: Powerful desktop interfaces with WPF and WinForms.
• Mobile and Cross-Platform: Applications for Android, iOS, Windows, and macOS with .NET MAUI using a single codebase.
• Game Development: Unity game engine runs on C#, making it one of the most popular languages in the game industry.
• Microservices and APIs: Minimal APIs, gRPC, and cloud-based microservice solutions.
• Cloud and IoT: Cloud services and IoT applications with Azure integration.

Your First C# Program!

using System;
class Program  
{      
    static void Main()      
    {          
        Console.WriteLine("Hello .NET World!");      
    }  
}  

This simple example demonstrates the basic working principle of the C# language. using System; imports the core .NET library, the Main method is the entry point of the program, and Console.WriteLine prints output to the console.

Summary

C# is a modern, type-safe, and versatile programming language. Thanks to the .NET ecosystem, it is possible to develop applications that run across different platforms. Starting with a simple console application, this journey extends to web services, mobile apps, desktop software, and game engines.