Which are popular C# interview questions? What are all the C#
important topics for an experienced interview? What should I know about the C#
Interview? What should I ask a .NET developer?
C# interview questions are likely to be technical and require
critical thinking. No matter if you’re a hiring manager or a developer, this
blog post can help you practice some of the most popular C# interview questions
and answers!
Let’s dive in!
C# is a multi-paradigm, general-purpose programming language. C#
covers static typing, strong typing, lexically scoped, imperative, functional,
declarative, generic, object-oriented, and component-oriented programming
disciplines. C# is a widely-used programming language for operating systems.
Also, the software testing sector has a high demand for experienced C#
developers.
Top 21 C# interview questions and answers
1.
Which are the four steps involved in the C#
code compilation?
Here are four steps of code compilation in C#:
o Source code
compilation in ‘Managed code.’
o Newly created code
gets clubbed with assembly code.
o The Common Language
Runtime (CLR) gets loaded.
o Assembly execution
goes through CLR.
2.
Which are the various ways to pass parameters
in a method?
The various ways of passing parameters in a method include:
o Output
parameters: Let the method return
more than one value.
o Value parameters: The formal value copies and saves the
value of the actual argument, allowing the formal parameter to be changed
without impacting the actual parameter’s value.
o Reference parameters: The formal argument preserves the actual
parameter’s memory address, thus any change to the formal parameter will affect
the actual argument as well.
3.
What are Managed and Unmanaged codes?
‘Managed code’ refers to code that is executed by the Common
Language Runtime or CLR. The .Net framework, which employs the garbage
collector internally to clear up unwanted memory, gives it the name ‘Managed
code.’
‘__Unmanaged code’ is executed by a framework other than .Net runtime or
outside the .Net framework.
4.
What is a Class and an Object in C#?
A ‘Class’ is a set of methods and properties that represent a
real-time entity. All of the actions are grouped together in a class.
An ‘Object’ is a block of allocated memory that can be saved as Variables,
Arrays, or Collections.
5.
Where are the steps of Code compilation in C#?
Code compilation has four steps which include:
o Compiling ‘Source
code’ to ‘Managed code’ using C# compiler.
o Executing the assembly
by CLR.
o Combining the new code
into assemblies.
o Loading the CLR.
6.
Explain the difference between the Virtual
method and the Abstract method
Virtual methods require a default implementation. However, there
is no implementation for an Abstract method.
7.
What is an Escape Sequence? Name the sequences
in C#.
A backslash denotes an escape sequence (\). The backslash
denotes that the character after the backslash is a special character. A single
character is considered an escape sequence.
8.
What is Serialization?
Serialization converts a code to its binary format.
Serialization can be readily saved and written to a disc after being converted
to bytes.
Serializations are useful for preserving the original version of the code and
retrieving it afterwards.
9.
Differentiate between Continue Statements and
Break?
Here is the difference between Break and Continue statements:
o Continue statement: Used to jump to the next iteration of
the loop after skipping a particular iteration.
o Break statement: Used to exit the loop by skipping the
next statements of the current iteration.
10.
What is the difference between finalize and
finalize blocks?
The Finalize block is called after the try and catch blocks have
been completed. This block of code gets executed regardless of the exception
that has been caught.
The Finalize method is called just before garbage collection. The Finalize
method’s top priority is to clear unmanaged code, which is triggered
automatically anytime an instance isn’t recalled.
11.
What is a Partial Class?
C# allows developers to split a single class file into numerous
physical files. To do so, they need to employ the Partial. This capability
assists developers in breaking down large class files into several little
physical files.
12.
Can you differentiate between method
overriding and method overloading?
Method overriding changes the definition of the derived class,
which changes the behavior of the method.
Under the same class, method overloading is the process of defining the same
name method with several signatures.
13.
What is a constructor, and what are its
different types?
A constructor is a unique method with the same name as the
class. Even if a constructor is not ready, the compiler creates a default
constructor in memory at the time of creating an object of the class. The
constructor initializes the object with some default values. Constructor
types include default, parameterized, copy, static, and private constructors.
14.
What is a destructor in C#?
The garbage collector automatically manages a destructor,
clearing memory to free up resources. Internally, System.GC.collect() is used
for this function. If necessary, a destructor can explicitly clear memory to
free up resources.
15.
What is inheritance?
Inheritance is a feature of object-oriented programming that
allows developers to create a base class with defined functionality, such as
data and behavior, and create derived classes that inherit or override that
functionality.
16.
Explain the steps to implement multiple
interfaces with the same method name in the same class.
This is a trick question. Though the implementation is possible,
developers will avoid doing it. A knowledgeable candidate might say: “I would
avoid implementing several interfaces with the same method name within the body
of the function. Instead, the name of the interface would be explicitly
provided in the method’s body. The compiler will figure out which interface
methods are being used, addressing the problem.”
17.
What is a sealed class?
When there is no need to inherit a particular class further, or
it is necessary to prevent that particular class from being inherited, the
class is turned into a sealed class. To make a sealed class, developers use the
‘sealed’ keyword.
18.
What is enum?
An enum is a value type. Enum functions as an enumerated list,
which is a collection of connected constants. The types of enums are int,
float, double, and byte.
To generate a numeric constant, developers use the .NET framework enum. The
enumeration element’s default value is int. The first enumerator has the value
0 by default and each subsequent enumerator increases by one like an array.
Here is a sample syntax: enum Day {Mon, Tue, Wed, Thu, Fri, Sat, Sun};
19.
What is serialization?
If developers wish to send an object across a network, they will
have to turn it into a stream of bytes. The process of transforming an item
into a stream of bytes is known as serialization.
20.
What is multithreading?
A thread is a process that runs any code block in C#. A thread
is the program’s execution path. Simple programs can run in a single thread,
but most modern programs employ multithreading.
Multithreading divides a process’s execution into numerous threads, allowing it
to run simultaneously and more efficiently. Multithreading also allows
developers to run multiple tasks at the same time.
21.
What are generics in C#?
Generics in C# include four action items which are as
follows:
o Increase performance.
o Increase type safety.
o Reduce repeated code.
o Make reusable code.