C# Basics

Part A: What is C#? - 10 mins
C# (pronounced C-Sharp) is a modern, object-oriented programming language developed by Microsoft in 2000.

Why learn C# in 2026:

• Versatile: One language for Web (ASP.NET), Mobile (MAUI), Desktop, Games (Unity), Cloud and AI.
• Beginner Friendly: Clean syntax, similar to Java and C++ but easier.
• High Demand: Used by enterprises, startups, and game studios. Strong job market.
• Powerful Tooling: Best-in-class IDEs and free .NET platform.

Part B: The .NET Ecosystem Explained - 15 mins
This is where most beginners get confused. Explain it simply:

Think of it like this: C# is the language you write, .NET is the platform that runs it.

.NET has 3 main parts:

1. CLR (Common Language Runtime): The engine. It compiles your code, manages memory, and runs your app. Your C# code doesn't run directly on Windows, it runs on CLR.
2. BCL (Base Class Library): A huge collection of ready-made code. Need to work with files, strings, dates, database? It's already in BCL. You don't have to build from scratch.
3. Languages: .NET supports C#, F#, VB.NET. You are learning C# which is the most popular.

Important Clarification for Students:

• .NET Framework = Old, Windows-only (2002-2019)
• .NET Core / .NET 5 / 6 / 7 / 8 / 9 = New, Cross-platform, fast, open-source. This is what we use today. .NET 8 is the current LTS version.

Flow of Execution: You write C# code -> Compiler converts it to IL (Intermediate Language) -> CLR converts IL to machine code and runs it.

Part C: Setup and First Program - 15 mins

Tools Needed:

1. .NET SDK 8 or 9: The engine to build and run.
2. IDE: Visual Studio 2022 (Best for Windows) OR VS Code + C# Dev Kit (Lightweight, works on all OS).

Your First Program:

Show these commands in terminal:

Bash

dotnet --versiondotnet new console -n MyFirstAppcd MyFirstAppdotnet run

Then show the code and explain EVERY line:

C#

using System; // Importing tools from .NET Base Class Library
class Program // A container for your code{    static void Main() // The starting point of every C# app    {        Console.WriteLine("Hello, World!"); // Print text to screen    }}

4 lines hidden

Common Doubts to Address:

• Why using System? Because Console lives inside it.
• Why static void Main? Because .NET needs one fixed entry point.
• What is ; and { }? Semicolon ends a statement, braces group code.

3. Live Demo Task For Video

Do this on screen: Create a program that prints your name, your city, and what you want to build with C#.

4. Recap - 2 mins

• C# is the language, .NET is the platform that runs it.
• CLR runs the code, BCL gives you pre-built features.
• We use modern .NET (8/9), not old .NET Framework.
• Every C# app starts from Main() method.