Ace The Coding Interview: Essential .NET Interview Questions
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Ace The Coding Interview: Essential .NET Interview Questions

The ultimate guide to mastering the tech interview: programming questions and solutions. Get more interviews & job offers

About the Book



This book contains over 170 REAL interview questions you're going to be asked during your interviews.

If you’re not interested in gaining more knowledge and confidence about this topic, please don't buy it. However, it helps you become more prepared for your next interview.

If you’re still here, make sure you read every lesson with a lot of attention. While reading it, please do the following exercise: imagine yourself taking an interview, not knowing that specific question and the interviewer is explaining it to you.

If you're still here...


Imagine yourself walking out the door after one of your greatest interviews ever; with that big smile on your face and being 100% confident you'll get the job. That's what I want to achieve by writing this book, which is full of tips, problems, and answers that will get you hired.

Technical interviews are very different compared to normal ones and the golden rule is always to spend enough time and effort on preparation. This doesn't mean you don't need people skills. You need them for sure and I'll tell you during the course why. In the end, my goal is to make you enjoy the process of walking to an interview.

However, if you feel like an interview has not gone well, just consider it a learning experience.

The book is split into 3 major parts: the first one for beginners, the second one for intermediate developers and the third one for seniors, so you can skip to the section you’re interested in. However, I recommend you go through all of them because a hard question for me can be an easy one for you and vice-versa. 

Each of the 3 major sections can contain lectures from C#, SQL, Javascript, HTML, CSS or GIT areas, so I’m covering everything a full stack developer can be asked during an interview.

By the way, I’m happy to receive feedback from you. If you think a question is not presented or it’s not presented very well, just let me know and we’ll improve it together. I’ll make sure you are mentioned. 

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    • Computers and Programming
    • C#
    • Technical Communication
    • JavaScript
    • Web Development
    • Git
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About the Author

Ion Cosmin Grigore
Ion Cosmin Grigore

Cosmin grew up in Ploiesti and graduated from the University Politehnica of Bucharest. He has over 8 years of professional experience in software development, having had the opportunity to improve his teaching and leadership skills.

He is passionate about personal development, nurturing emotional intelligence, social and financial skills in every possible way, this being proven by the numerous personal projects we worked on, including some related to cryptocurrencies.

With an exceptional eye for details when it comes down to helping others achieve their goals, he considers everyone can learn if they take the right path.

If you want to find more about him, we recommend following him on Facebook & LinkedIn.

Personal Note:

Hey everyone! I like people who want to overcome their current condition and hate arrogant people and those who do not want to evolve.

I hope my lectures help you achieve your extraordinary goals.

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Table of Contents

TL;DR. 9

The Purpose of this guide. 9

Is this guide for you?. 9

Few things about me. 10

What you’ll find here?. 10

Requirements: From A Non Programmer To Full Stack .NET Developer. 11

How to stand out: Top 3 Tips. 12

Before the interview: No Technicalities Yet….. 13

Contact phase: LinkedIn, Resume. 13

Different types of technical interviews. 13

But I don’t Have Enough Experience Myth….. 14

This Is What I Look For When Going To An Interview.. 14

This Is How I Usually Take Interviews. 15

How Is This Course Structured?. 16

Important. 16

.NET Interview Questions For Level 0 – Beginner. 17

OOP principles: Encapsulation. 17

OOP principles: Polymorphism and Inheritance. 18

OOP principles: Abstraction. 21

C# Quiz. 24

C# Basics: Class vs Object. 25

C# Access Modifiers: Public, Protected, Private, Protected Internal and Private Protected. 25

C# Quiz. 29

C# Loop Functions: While vs For. 30

C# Loop Functions: Do-While vs While. 31

C# Loop Functions: Continue vs Break. 32

C# Basics: Abstract Methods vs Virtual Methods. 33

C# Quiz. 35

C# Basics: What Is A Partial Class?. 35

C# Basics: What Is a Sealed Class? When you want to use it?. 37

C# Interfaces: Interface vs Abstract Class. 38

C# Interfaces: Access Modifiers. 40

C# Quiz. 40

C# Interfaces: Implementing 2 interfaces with same method. 41

C# Basics: Static vs Non Static. 42

C# Basics: Const vs Readonly. 44

C# Quiz. 45

C# Basics: Overriding vs Overloading (Contructor, Method, Operator). 45

C# Basics: Hiding methods (Inheritance). 48

C# Basics: Private Constructor. 50

C# Basics: Static Constructor. 52

C# Quiz. 53

C# Immutability: String vs StringBuilder. 53

C# Parameters: Pass by value. 54

C# Parameters: Pass by Reference. 54

C# Parameters: Ref vs Out (Differences and Limitation). 55

C# Basics: Boxing vs Unboxing. 57

C# Basics: Struct vs Class. 57

C# Quiz. 59

C# Basics: As vs Is. 59

C# Exceptions: Throw Exception vs Throw.. 60

C# Exceptions: Can you have a try block without catch?. 61

C# Exceptions: Why to use finally block?. 62

C# Quiz. 63

C# Basics: What is an attribute?. 63

C# Basics: Get vs Set. 64

C# Basics: Practical Use-Cases for Closures. 65

C# Basics: What Is Caching?. 66

C# Quiz. 68

C# Generics: Classes Constraints. 68

C# Basics: Extension methods. 70

C# Basics: Anonymous Types. 71

C# Quiz. 72

C# Basics: Exe vs DLL. 72

C# Basics: GAC. 73

C# Basics: Object Pool 73

C# Basics: Deferred Execution vs Immediate Execution. 76

C# Basics: What is a Stream?. 77

C# Quiz. 78

C# Concepts: TDD, DDD.. 78

MVC: GET vs POST. 79

MVC: What Is A Controller? Class Vs Controller. 79

MVC: Request Flow.. 80

MVC: Model, View and Controller (who knows who). 80

MVC: ViewState vs SessionState. 81

C# Quiz. 82

XML: What is an XSD file?. 83

XML: XML fragment vs XML document. 83

API: What is CORS?. 83abst

GIT: What does git reset?. 83

GIT: What does git push origin master?. 83

HTML: div vs span. 84

HTML: Why is it a good idea to split HTML and CSS?. 84

HTML: What is the difference between classes and ids?. 84

HTML: What is the difference between margin and padding?. 84

HTML: Does a hyperlink apply to text only?. 85

Quiz. 85

Javascript Basics: Session Storage vs Local Storage. 85

Javascript Basics: What is associative array?. 86

Javascript Basics: Use Strict in Javascript?. 87

Javascript Basics: NaN.. 88

Javascript Basics: Working of timers in JavaScript? Any drawbacks?. 88

Javascript Basics: Enumerate data types. 88

Javascript Basics: Define event bubbling in Javascript. 89

Javascript Basics: Javascript vs Typescript?. 90

Javascript Basics: Is Javascript case sensitive?. 91

Javascript Basics: Object Inheritance in JavaScript. 91

Javascript Basics: this keyword in Javascript. 93

Javascript Basics: What Is Ajax?. 95

SQL: Basic SQL Syntax. 96

SQL: Inner Join, Outer Join, Left join, Right join. 97

SQL: Cursor. 99

SQL Quiz. 100

.NET Interview Questions For Level 1 – Intermediate. 100

POO Principles: KISS, DRY, TDA, YAGNI 100

POO Principles: Inheritance Access Modifiers. 101

C# Topics: Managed vs Unmanaged Code. 105

C# Topics: Stack vs Heap. 106

C# Topics: IL, CIL, MSIL, CLI, JIT. 108

C# Topics: Strong Typing vs Weak Typing. 109

C# Quiz. 110

C# Topics: Difference between a.Equals(B) and a == b. 110

C# Topics: Difference between early-binding and late-binding. 111

C# Topics: Diffrence between typeof vs .GetType()?. 111

C# Topics: LINQ vs Stored Procedures. 112

C# Topics: Can we use ‘this’ inside a static method in C#?. 112

C# Topics: Delegates, Multicast Delegates, Generic Delegates, Events. 113

C# Quiz. 117

C# Topics: Serialization (Binary vs xml). 117

C# Topics: Generic Classes Performance Improvements. 118

C# Topics: SQL Deadlock vs C# Deadlock. 118

C# Topics: What Is Reflection?. 119

C# Quiz. 120

C# Collections: Yield return. 121

C# Queries: List interfaces (ICollection, IList, IEnumerable). 122

C# Queries: IEnumerable vs IQueryable. 123

C# Multithreading: Thread vs Process. 124

C# Multithreading: Deadlocks (lock, semaphores, mutex) 125

C# Multithreading: SystemThread, ThreadPool, Delegate.BeginInvoke. 126

C# Multithreading: Send data between processes. 127

C# Multithreading: States of a Thread in C# - Unstarted, Ready, Not Runnable, Dead. 129

SOLID Principles: SRP, OCP, LSP, ISP, DIP. 129

C# Topics: What is DI? What is IoC?. 134

C# Topics: Dispose vs Finalize. 136

Design Patterns: What design patterns are used throughout .NET framework?. 137

HTML: What is a doctype good for?. 137

Javascript: Private Members inside a Javascript object. 138

Javascript: this keyword in Javascript. 139

Javascript: Types of errors in JavaScript - Load Time, Runtime, Logical 141

Javascript: What are true private methods in JavaScript? What is the drawback?. 142

Javascript: Methods to empty an array in Javascript. 143

Javascript:What is Function Hoisting in Javascript?. 143

.NET Interview Questions For Level 2 – Advanced. 146

C# Advanced: Garbage Collection Phases. 146

C# Advanced: Explain Query Comprehension. 146

C# Advanced: Covariance vs Contravariance + in/out keywords for generics. 148

C# Advanced: NET Remoting - Serializable Types, MarshalByRef. 149

C# Advanced: When would using Assembly.LoadFrom or Assembly.LoadFile be appropriate?. 150

C# Advanced: What are the benefits of a strongly named assemblies?. 151

C# Advanced: What are Expression Trees?. 152

C# Advanced: What is CI/CD? Explain the flow. 153

C# Advanced: Cloud vs On-Premise? Advantages vs Disadvantages. 155

C# Advanced: Can a thread have parameters?. 156

C# Advanced: Can we overload generic method in c#?. 156

C# Advanced: Chain of responsibility pattern vs decorator?. 158

C# Advanced: When would you use the builder pattern? Why not just use a factory pattern?. 160

C# Advanced: How can you stop a thread in C#?. 161

Javascript: Few last Javascript tips. 162

SQL: Index Fragmentation  164

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