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Free tutorial · 22 lessons

C# Tutorial

Learn C# and .NET step by step: variables, strings, control flow, methods, classes, interfaces, records, generics, collections, LINQ, exceptions, nullable types, async/await, files and JSON — every example shown with its output.

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C# Basics

  1. C# Introduction — What C# and .NET are, what you can build, and a first program.
  2. C# Get Started — Install the .NET SDK, create a console app and run it.
  3. C# Syntax and Output — Statements, blocks, comments, Console.WriteLine and string interpolation.
  4. C# Variables and Data Types — Declare typed variables, use var, const and the built-in types.
  5. C# Strings — String methods, comparison, verbatim and raw strings, and StringBuilder.
  6. C# Operators and Math — Arithmetic, comparison, logical, null operators and the Math class.
  7. C# History & Versions — How Microsoft created C# and .NET, how they became open source and cross-platform, every C# version from 1.0 to 14 on one timeline, and which .NET version to use today.

Control Flow

  1. C# If Else and Switch — Conditions, switch statements and switch expressions with patterns.
  2. C# Loops — for, while, do-while, foreach, break and continue.
  3. C# Arrays — Single and multi-dimensional arrays, indexes, ranges and Array methods.
  4. C# Methods — Define methods with parameters, defaults, named arguments, out/ref and overloading.

Object-Oriented C#

  1. C# Classes and Objects — Classes, constructors, fields, properties and methods.
  2. C# Inheritance and Interfaces — Base classes, virtual/override, abstract classes and interfaces.
  3. C# Records, Structs and Enums — Immutable records with value equality, structs and enums.
  4. C# Generics — Generic classes and methods with type constraints.

Collections and LINQ

  1. C# Lists and Dictionaries — List<T>, Dictionary<TKey,TValue>, HashSet<T> and collection expressions.
  2. C# LINQ — Query collections with Where, Select, OrderBy, GroupBy and aggregates.

Advanced C#

  1. C# Exceptions — try, catch, finally, throw, custom exceptions and using.
  2. C# Nullable Reference Types — string vs string?, null warnings and safe null handling.
  3. C# Async and Await — Task, async/await, Task.WhenAll and cancellation.
  4. C# Files and JSON — Read and write files with File, and serialize JSON with System.Text.Json.

Next Steps

  1. C# Next Steps — ASP.NET Core, Entity Framework, testing and interview practice.