C# Interview Preparation for Beginners

C# interviews for freshers keep returning to the same topics: how C# runs on .NET, value and reference types, strings, object-oriented design, collections and LINQ, exceptions and resource cleanup, and , and a little dependency injection and SOLID. This collection is a complete, ordered path through them for freshers (0 to 1 year of experience): learn a topic, practise it with a short program, then test yourself.

How the path is organised

1. Start here (step 1): the 30-day roadmap and how to set up a practice project.
2. Language fundamentals (steps 2 to 6): C# versus .NET versus the CLR, value and reference types, boxing, strings, and two warm-up coding problems.
3. Object-oriented programming (steps 7 to 10): inheritance, polymorphism, //, records and pattern matching, with a quiz.
4. Collections, generics and LINQ (steps 11 to 19): dictionaries and lists, generics, delegates and events, LINQ, coding problems, with a quiz.
5. Exceptions, memory and async (steps 20 to 25): /, , the garbage collector, and , with a quiz.
6. Design, testing and interview readiness (steps 26 to 31): dependency injection, SOLID, unit testing, the 25 mistakes to avoid, 30 coding problems, the 50 most-asked questions, and a final mixed quiz.

The examples target modern .NET (.NET 8 or later) and C# 12 or later, and were compiled and run on .NET 10. Each step also has its own page, so you can jump straight to the topic you need.