Introduction to C# in 2025: Where to Start in Practice

Introduction to C#: Where to Start in 2025 in Practice

C# (pronounced "C sharp") is a modern, multi-paradigm programming language from Microsoft that is part of the .NET ecosystem. In 2025, C# remains one of the most in-demand languages for developing desktop applications, web services (ASP.NET Core), mobile applications (Xamarin / .NET MAUI), and even games on Unity. If you have decided to start learning C# from scratch, this guide will help you take your first practical steps.

Why Learn C# in 2025?

C# is actively evolving. Annual updates bring new features, improved performance, and code security. Key advantages of the language:

• Cross-platform: .NET runs on Windows, Linux, and macOS.
• Strong typing: helps avoid many errors at compile time.
• Large community: many libraries, tools, and ready-made solutions.
• High salary: C# developers are in demand on the job market.

Step 1: Installing .NET SDK and Setting Up the Environment

The first practical step is to install the .NET SDK (Software Development Kit). This is a set of tools needed to compile and run C# programs.

1. Go to the official website dotnet.microsoft.com.
2. Download the latest version of the .NET SDK (as of 2025, this is .NET 9 or .NET 10).
3. Install the SDK by following the installer instructions.
4. Open a terminal (command line) and verify the installation with the command:

dotnet --version

If you see a version number, everything is ready. For writing code, you can use any text editor (Notepad++) or a full-fledged IDE, such as Visual Studio Community (free) or Visual Studio Code with the C# extension.

Step 2: Creating Your First Console Program

Let's create a simple console application that outputs a greeting. Open a terminal and run the commands:

mkdir MyFirstAppcd MyFirstAppdotnet new console

These commands will create a project folder and generate the Program.cs file. Open it in an editor. You will see something like this:

// See https://aka.ms/new-console-template for more informationConsole.WriteLine("Hello, World!");

Change it to a more detailed example:

using System;

class Program{    static void Main(string[] args)    {        Console.WriteLine("Enter your name:");        string name = Console.ReadLine();        Console.WriteLine($"Hello, {name}! Welcome to the world of C#.");    }}

Run the program with the command:

dotnet run

The program will ask for a name and then greet you. Congratulations, you have written your first interactive C# program!

Step 3: Basics of Syntax in 10 Minutes

Let's break down the basic language constructs. C# is a strongly typed language, so every variable must have a declared type.

Variables and Data Types

int age = 25;              // integerdouble price = 19.99;      // floating-point numberstring city = "Moscow";    // stringbool isStudent = true;     // boolean value

Conditional Statements

if (age >= 18){    Console.WriteLine("You are an adult.");}else{    Console.WriteLine("You are a minor.");}

Loops

for (int i = 0; i < 5; i++){    Console.WriteLine($"Iteration number {i}");}

Methods (Functions)

static int Sum(int a, int b){    return a + b;}

// Method call