C# Interview Questions and Answers - UPDATED 2024

Beginner Level C# Interview Questions and Answers

Get an understanding of the beginner Level C# Interview Questions and Answers to advance frequently asked C# interview questions and answers first.

These C # interview questions for experienced professionals and fresher’s draw an idea of the questions type and pattern most slightly to be asked by the interviewers. It has never been any better with mock preparations.

Frequently asked C# interview questions for experienced professionals and for freshers to get the right job includes,

 

1) List some of the features with the definition of C#.

A programming language is used to write software for a website, a desktop application, or a mobile application. All of these types of software are built using a programming language.

 In C# we have .Net framework that has virtual machines like Common Language Runtime or CLR & Base class Libraries. Any application code is compiled and run into windows; .Net framework comes into action by executing it. We use Visual studio .Net in the Microsoft word to write the codes. 

This allows us what type of application we are going to build and what programming language we are going to use. There is plenty of programming language that the .Net supports but C# is easy to learn, easy to work with, and doesn’t sacrifice power and control.

C# is known as an object-oriented programming language which means we build and model our application by looking at its blueprint. These blueprints are classes that help us to model our application. Every time a user uses this application, then one part of these blueprints get turned in to an actual object in memory to work with.

 

2) Mention the different types of comments in C#?

To be specific comments are the message you put on your code or you want to deactivate some lines of code and see how it works without them or describe what some of your code is trying to perform.

A comment line uses a double slash followed by a comment. It breaks up the code and makes it look a little nicer if it is an advanced code then it's wise to put in a couple of comments just to explain what is going on.

Example:

// These two lines change the color of the text.

Comment Blocks must start with a “/” followed by an “*” & it must finish with an “*” and a “/”. You can have as many lines in between them as you like. And then you can add a Multi-line comment to describe things that are going on.

Example:

/* Comment line

*Comment block

*comment web report

************************/

* 

Comment web report: You can do it before the static void main, or you can do it for the class program. You do three “///” & you will find XML to pop up where you write the summary about the void main in here.

Example;

/// This is comment web report, looks great!

One of the common C# interview questions for experienced professionals.

 

3) What are some of the IDE’s provided by Microsoft for C# development?

IDE or Integrated Development Environment is a piece of software that helps us to write codes. IDE makes developing applications programs easier. It acts as a text editor, debugger, and compiler all in one.

There are many different types of IDEs; some common IDEs are Visual Studio, Xcode, Android Studio, Pycharm, eclipse, sublime, Adam, to name a few.

 Example:

> if (programmer)

> {

> use This = True

> }

 

4) Chart out the process of code compilation in C#.

We have language independency when we are working with .Net framework, the complete compilation process for any particular language in .Net framework we can classify the compilation process into two parts.

The first step involves compiling of the language by the compiler and then redirecting it to an intermediate language. While in the second phase the compilation is done by the JIT or Just-In-Time.

 

 

5) Differentiate between managed and unmanaged code?

The code that executes with the CLR instead of an operating system is called as a Managed code. In the managed code the runtime will provide services like a garbage collector, type checking & exception handling. The code is compiled by the language compiler into an Intermediate language.

While a code that does not execute under CLR and is directly executed in the operating system is called unmanaged code. It does not provide services like garbage collector & type checking, it should be taken care of by the programmer itself. He should write the code to deallocate the memory. Here code will be compiled into native code.

 

Intermediate Level C# Interview Questions and Answers

Enlisted below are the C# interview questions for experienced professionals and beginners that will sum your insights on Intermediate Level C# Interview Questions and Answers. It is equally important to get a grasp of the different questions' weightages and their level.

C# developers looking for the perfect C# job role to enhance their C# understanding further should seek C# interview questions for experienced professionals.

 

1) Differentiate Finally Block and Finalize Block.

At the end of performing the try-and-catch blocks, the final block is declared. The final block basically utilized to handle the exception. When some sort of exception is found in the block of code while performing the block, normally these block codes contain cleaner codes, to clean the exception.

When the exception is found, then the next should be garbage collection. In these types of circumstances, the Finalize method is called for the cleaning operation to run successfully.

 

2) What do you know about managed and unmanaged codes?

The managed code is that type of code that is performed or executed by Common Language Run-time. This indicates that the application codes hinge on the .NET platform. At the same time, unmanaged code can be defined as the codes that are performed by a run-time application that doesn’t belong to the .NET framework. In those cases, the memory, security, and execution of unmanaged codes totally depend on that different run-time application.

 

3) Define an Object in C#

The Object can be referred to as an instance of any class. In order to access the methods of a class, one has to make use of objects. To create or generate an object, the developers should use a separate and fresh keyword. The creation of an object takes place in the memory location of a class. The memory location of that class comprises the required data of methods, behavior, and variables of the class.

 

4) Define class

In general, a class can be defined as an outline of an object. The class decides the basic functions and abilities that an object should possess. As the class is an object’s blueprint, an object can be called as an instance of the class. It is the class that helps the developers to produce an object. However, in C#, the class is basically termed as a keyword of class or class keyword.

 

5) What is an abstract class in C#?

An abstract class can be defined as a type of class that consists of a particular technique, and it is written with “Abstract” keyword. As the abstract class has a specific approach, an object cannot be instantiated from this class.

 

6) How will you define sealed classes in C#?

A sealed class is a type of class that is created in such a way that it cannot be inherited by C#. Unlike the abstract class, a sealed class can be instantiated, but it cannot be inherited. The main purpose of the sealed class is to limit the inheritance of class.

 

7) What do you mean by partial class in C#?

The partial class is a type of class that divides the definition of a single class into multiple classes. This segregation of single class definition can be carried out by means of the same source codes or various different source codes.

It is possible to create one class definition in numerous files, but that is accumulated as a single class at the run-time application. And then an instance or object of that class is produced. With the help of that object, the user can easily enter into all the methods of the class from various source files. The partial class is depicted by the keyword “Partial”.

 

8) What are the fundamental OOP concepts in C#?

One can list down four fundamental Object-Oriented Programs concept, and those are:

 

Inheritance

When the characteristic feature is transferred to create another class without any modification, then such activity is called inheritance. In this concept, the class from which its features are transferred is called a Base class or Parent Class. And the class in which those features are “transferred on” is called as Child Class.

 

Polymorphism 

Polymorphism in the programming world can be defined as the ability of an object that permits an object to transform into different states.

 

Encapsulation

Encapsulation is a process in which multiple data are bound together in one class. And the user cannot get access to that data directly, but it should be done by prefixing an underscore.

 

Abstraction

This is a process in which the developers will have the command to show a specific detail, and they can hide data from the users which are not important from the user’s point of view. This process is necessary to resolve the complicated issues by designing and creating classes that are suitable to solve specific issues. Further, for an abstract class, an object cannot be instantiated.

 

9) How would you inherit a class into another class in C#?

Various platforms use various codes to inherit any class. In the case of C# colon is used to operate inheritance.

 

10) What is Method Overloading in C#? Elucidate.

The method overloading is a common process that is carried out in C# to create a number of methods that will contain the same name and specific signatures. This process is carried out with the same class. On completion of the method overloading process, the compiler initiates operations to invoke specific actions on the basis of method overloading.

One of the common C# interview questions for experienced professionals to revise.

 

11) Distinguish between Method Overloading and Method Overriding in C#?

Method Overriding is a process in which the basic definition of a derived class is changed. And eventually, this process alters the method behavior of the derived class. 

Whereas method overloading can be defined as a process in which multiple methods are generated that comprise the same name and different signatures under the same class.

 

12) What is Stream Reader and Stream Writer class in C#?

There are certain data that cannot be read casually, in order to read such data specific classes is used are Stream Reader and Stream Writer. These are the two classes that originate from namespace.System.IO. And these classes are used to read charact90 and write Reader Based data correspondingly.

 

13) Define Interface.

The interface can be defined as a class that comprises property declaration, attributes declaration, and event declaration.

 

14) How will you differentiate Virtual Method and Abstract Method?

The virtual method can be defined as a method that comes along with a default implementation. And it allows the developers to override it by simply using the keyword override.

The abstract method, on the other hand, is a method that is present in the abstract class. And it is compulsory for the derived class to use the abstract class. Further, it basically doesn’t come along with an implementation whatsoever. And there is no necessity to override the abstract method.

 

15) What do you mean by Namespace in C#?

Namespaces can be defined as a command that can be utilized to organize and manage projects of huge codes. The namespace used in the C#, but the most prominently used namespace in C# is the “System”. It is permissible for a user to generate their specific namespaces and to use one namespace on another namespace is called Nesting.

 

16) How will you define the Using Statement in C#?

The “using” can be defined as a keyword that is executed to signify a specific Namespace.

 

17) What is a Jagged Array in C#?

In C# there is a term called a Jagged Array. It generally means an “array of arrays”. Its components are arrays, and these components may possess various dimensions. This reflects the possible length-wise difference of the array index.

 

Advanced Level C# Interview Questions and Answers

The advanced level C# Interview Questions and Answers brings a comprehensive understanding to test your understanding of C# knowledge. Apart from interview readiness for related C# interview questions for experienced professionals, it will also cover the type of question to tackle for.

Here are the few Advanced Level C# Interview Questions and Answers,

 

1) Define Delegates?

A delegate is a type-safe function pointer. It holds the reference of the method & then calls the method for execution. In C# we can call a method in two types:

- Static

- Delegate

There are three steps to calling a method by using a delegate:

- Defining a delegate by [] delegate void|type( [])

- Instantiating the delegate- it is the process of creating the instance of the delegate and in the process, you have to pass the method name as a parameter to the delegate constructors.

  AddDelegate ad = new AddDelegate(p.AddNums);

  SayDelegate sd = new SayDelegate(Program.SayHello);

- Now call the delegate by passing required parameter values, so that internally the method which is bound with the delegate gets executed.

 

2) Define Generics?

Generic is introduced in C# 2.0 it allows us to design classes and methods decoupled from the data types. These reusable code classes decrease the code redundancy, the namespace, and parameterized type are used to create a generic collection.

 

3) Explain Deadlock with an example?

Let’s say, we have two threads and two resources as depicted below in the figure.

 

 

Thread 1 has already exclusively acquired a lock on Resource1 and wants to achieve a lock of Resource 2. At the same time, Thread 2 has already acquired a lock on Resource 2 & wants to acquire a lock on Resource1. Two threads never give up their locks hence a deadlock is formed.

A deadlock is a situation in which 2 or more transaction is waiting for one another to give up the lock. Here T1 is waiting for T2 & vice versa. Lock(X) is exclusive lock that can both read and write.

Whereas, the Lock(S) or shared lock can only read operations. There are three necessary conditions in Deadlock:

- Hold & Wait

- Mutual Exclusion

- No Preemption

- Circular weight

 Intermediate Level C# Interview Questions and Answers

 

4) What are Spawn Threads with thread pool?

A thread is a part of CPU or a multiple CPUs that is captured & used solely for the process. We could say that at any given time multiple threads run multiple processes. To see how threads work, take a look at this example.A 

Thread pool is nothing but a collection of threads. Here collection means preconfigured thread to serve incoming task-Async. A task function that runs asynchronously and is created first & helps to increase the application’s responsiveness. For example Google search example.

Public Static void ThreadCounter(i);

{

for  ( ( int i = 0; I < 10;i++)

        {

                        Console.Writerline(i);

                        Thread. Sleep(0);

           }                      

 

5) Illustrate Thread and explain multithreading?

To understand the perspective of multithreading let’s look into the concept of multitasking. OS to run these applications run simultaneously will make use of a process. A process is a part of the OS responsible to execute the application.

Each process runs one application. The windows OS also has background processes & these are windows services. 

Operating system:

- Process

- Thread

Thread is a unit that executes the logic into every application. Every application has by default one thread to execute the logic called “Main thread”. So, every program is by default a single-threaded model.

Using systems;

Class ThreadDemo

{

 Static void Main()

 {

 Console.WriteLine(“HelloWorld”)

 }

}

Compiling this code will run this logic:

Using systems;

Using system.Threading;

Class ThreadDemo

{

 Static void Main()

 {

   Thread t = Thread.CurrentThread;

t.Name = “Main Thread”;

 Console.WriteLine(“Current executing thread is : “+ Thread.CurrentThread.Name);

}

}

Here “t” refers to the executing thread.

The thread allows us to have multiple paths of execution going through our codes simultaneously. In a single-threaded model, actions are executed one after another or sequential in nature, but if, suppose the time lingers then we will get glitches like downtime in response.

To overcome this particular problem we can use the concept of multithreading.

Multi-threading contains more than one thread to execute. Meaning in one thread we will have multiple processes where each method executes simultaneously. Here OS shares the time period for each thread to execute.

In other words, our programs going to be able to branch off so that the application is going to be doing multiple things at the same time. You probably have one CPU with a few cores in it but we will have ten or more threads going at the same time.

The CPU switches between these threads giving little slices of time to each one and by cycling through them it’s going to give us the appearance that more than one thing is going on at the same time.

 

Conclusion

The above are the most important questions that are asked in the C# interview for C# interview questions for experienced professionals and beginners.

You will have to be thorough with all C# Interview Questions and Answers to pass in your interview.

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