C# Interview Roadmap for Beginners: A 30-Day Plan
C# and .NETbeginnerinterview-prepdotnet
Codevity Admin · 10/25/2026
Step 1 of 31 · C# Interview Preparation for Beginners · Stage 1: Start here
Codevity Admin · 10/25/2026
C# interviews for freshers (0 to 1 year of experience) follow a predictable pattern. There is a round of language fundamentals (value versus reference types, strings, == versus .Equals()), a block of object-oriented questions (virtual, override and new, abstract class versus interface), collections and LINQ, exceptions and IDisposable, async and await, a little on dependency injection and SOLID, and usually one or two small coding problems such as reversing a string or "two sum".
This roadmap turns that pattern into a 30-day plan and shows where each topic lives in this collection.
The examples target modern .NET (.NET 8 or later) and C# 12 or later, and they were compiled and run on .NET 10, the current long-term-support release. Where an older behaviour matters in interviews, the text says so. The old .NET Framework (up to 4.8.1) is Windows-only and no longer receives new features, but you may still be asked how it differs from modern .NET.
Code examples assume the implicit usings that new projects enable by default (System, System.Collections.Generic, System.Linq, System.IO, System.Threading.Tasks and a few more), so you will not see those using lines. Most examples are complete programs that use top-level statements, so you can paste one into Program.cs and run it.
Install the .NET SDK, then create a console project:
dotnet new console -o InterviewPrep
cd InterviewPrep
dotnet runUse Visual Studio, or Visual Studio Code with the C# Dev Kit. For every topic, replace the contents of Program.cs, run it, and then change the code and predict the result before you run it again.
| Days | Focus | Study this | Goal |
|---|---|---|---|
| 1 to 6 | Foundations: runtime, types, strings | C# vs .NET vs the CLR, value and reference types, strings | Explain how C# code runs, where data lives, and why strings are immutable |
| 7 to 14 | Object-oriented programming | OOP in C#, modern C# features, virtual, override and new, Types, Strings and OOP quiz | Design clean classes and avoid the method-hiding traps |
| 15 to 21 | Collections, generics, delegates and LINQ | Collections, generics, delegates and events, LINQ, Collections, LINQ and Delegates quiz | Filter and transform data without repeated enumeration |
| 22 to 28 | Runtime: exceptions, memory, async | Exceptions and IDisposable, garbage collection, async and await, Exceptions, Memory and Async quiz | Manage resources and write correct asynchronous code |
| 29 | Design | DI, SOLID and unit testing | Refactor tightly coupled code into testable code |
| 30 | Interview mastery | 25 mistakes, 30 coding problems, Top 50 questions | Run a full mock interview and answer under time pressure |
| Minutes | Activity | How |
|---|---|---|
| 15 | Say it aloud | Explain the day's main question in under 60 seconds, without filler words, and contrast it with a neighbouring concept |
| 35 | Study | Read the explanation, the memory implications and the edge cases |
| 30 | Type code | Write the examples yourself in a new console project. Test , empty collections and boundary numbers |
| 10 | Mistake journal | Write down every compiler error, exception and wrong assumption from today |
Reread your mistake journal on days 15, 22 and 29. It is the cheapest and most personal revision material you will ever have.
Start with C# vs .NET vs the CLR. Every step in this collection also has its own page, so you can jump straight to the topic you need.
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