Here, We see C# LinkedIn Skill Assessment Answer. This assessment test consists of 15-20 MCQs to demonstrate your knowledge of your selected skills. MCQs come from different topics – C# Assemblies and Extensions, C# Communication, C# Fundamentals, C# Networking, C# Objects, and Types.

List of all LinkedIn Skills Assessment Answer

C# LinkedIn Skill Assessment Answer

Q1. In which of these situations are interfaces better than abstract classes?

When you need to define an object type’s characteristics, use an interface. When you need to define an object type’s capabilities, use an abstract class.
Interfaces are a legacy of older versions of C# and are interchangeable with the newer abstract class feature.
When you need a list of capabilities and data that are class-agnostic, use an interface. When you need a certain object type to share characteristics, use an abstract class.✔
You should use both an interface and an abstract class when defining any complex object.

Q2. Which statement is true of delegates?

Delegates are not supported in the current version of C#
They cannot be used as callbacks.
Only variables can be passed to delegates as parameters.
They can be chained together.✔

Official documentation: Delegates

Q3. Which choice best defines C#’s asynchronous programming model?

reactive
inherited callback
task-based✔
callback-based

Official documentation: Task asynchronous programming model

Q4. How would you determine if a class has a particular attribute?

var type = typeof(SomeType);
var attribute = type.GetCustomAttribute<SomeAttribute>();
Code language: JavaScript (javascript)

var typeof(MyPresentationModel).Should().BeDecoratedWith<SomeAttribute>();
Code language: JavaScript (javascript)

Attribute.GetCustomAttribute, typeof(SubControllerActionToViewDataAttribute)
Code language: JavaScript (javascript)

D✔

Attribute.GetCustomAttribute(typeof(ExampleController), typeof(SubControllerActionToViewDataAttribute))
Code language: JavaScript (javascript)

Q5. What is the difference between the ref and out keywords?

Variables passed to specify that the parameter is an output parameter, while ref specifies that a variable may be passed to a function without being initialized.
Variables passed to ref can be passed to a function without being initialized, while out specifies that the value is a reference value that can be changed inside the calling method.
Variables passed to out can be passed to a function without being initialized, while ref specifies that the value is a reference value that can be changed inside the calling method.✔
Variables passed to ref specify that the parameter is an output parameter, while out specifies that a variable may be passed to a function without being initialized.

Q6. How could you retrieve information about a class, as well as create an instance at runtime?

reflection✔
serialization
abstraction
dependency injection

Official documentation: Reflection

Q7. What is this code an example of?

privatestaticobject objA;
    privatestaticobject objB;

    private static void performTaskA()
    {
        lock (objB)
        {
            Thread.Sleep(1000);
            lock (objA) { }
        }
    }

    private static void PerformTaskB()
    {
        lock (objA)
        {
            lock (objB) { }
        }
    }
Code language: JavaScript (javascript)

a private class that uses multithreading
multithread coding
thread mismanagement
a potential deadlock✔

Official documentation: Deadlocks and race conditions

Q8. What is the difference between an anonymous type and a regular data type?

Anonymous types don’t have type names✔
Anonymous types can only be static
Anonymous types can be used only in struts
Anonymous types don’t work with LINQ.

Official documentation: Anonymous Types

Q9. When would you use a Dictionary rather than an Array type in your application?

When you need a jagged collection structure
When you need to store values of the same type
When you need to store key-value pairs rather than single values✔
When you need an ordered, searchable list

Official documentation: Dictionary Class

Q10. What is the difference between a.Equals(b) and a == b?

The .Equals method compares reference identities while the == compares contents.
The .Equals method compares primitive values while == compares all values.
The .Equals method compares contents while == compares reference identity.✔
The .Equals method compares reference types while == compares primitive value types

Official documentation: Object.Equals

Q11. Which choice best describes a deadlock situation?

when you try to instantiate two objects at the same time in the same class or struct
when you are trying to execute an action after a user event is registered
when simultaneous instructions are waiting on each other to finish before executing✔
when you try to execute a series of events simultaneously on multiple threads

Official documentation: Deadlocks and race conditions

Q12. How does the async keyword work?

It allows access to asynchronous methods in the C# API
It allows thread pooling and synchronous processes in static classes.
It allows the await keyword to be used in a method✔
It allows access to synchronous methods in the C# API

Official documentation: async

Q13. What is an object in C#?

a class or struct, including its variables and functions
a primitive data type that can be created only at compile time
a value type that can be used only with an abstract class
an instance of a class or struct that includes fields, properties, and/or methods✔

Official documentation: Objects

Q14. Which code snippet declares an anonymous type named userData?

var<<!—->T> userData = new <<!—->T> { name = “John”, age = 32 };
var userData = new { name = “John”, age = 32 };✔
AType userData = new AType { name = “John”, age = 32 };
Anonymous<T> userData = new Anonymous<T> { name = “John”, age = 32 };

Official documentation: Anonymous Types

Q15. What will be returned when this method is executed?

public void userInput(string charParameters) { }

Nothing✔
a Boolean
a string variable
an integer

Official documentation: void

Q16. In what order would the employee names in this example be printed to the console?

string[] employees = { "Joe", "Bob", "Carol", "Alice", "Will" };

IEnumerable<string> employeeQuery = from person in employees
                                    orderby person
                                    select person;

foreach(string employee in employeeQuery)
{
    Console.WriteLine(employee);
}
Code language: JavaScript (javascript)

ascending✔
unordered
descending
first in, first out

Q17. Lambda expressions are often used in tandem with which of the following?

Namespaces
LINQ✔
Type Aliasing
Assemblies

Official documentation: Language Integrated Query (LINQ) Overview

Q18. What is the correct formatting for single-line and multiline comments?

/_/ – Single Line /_ – Multiline
// Multiline /_ Single Line _/
//\* Multiline / Single Line
// Single Line /* Multiline */✔

Q19. How do you make a method in an abstract class overridable?

Make it public
Make it static
Make it private
Make it virtual✔

Q20. How would you write code for an integer property called Age with a getter and setter?

public int Age { get – set }
public int Age: get set;
public int Age (get, set );
public int Age { get; set; }✔

Official documentation: Using Properties

Q21. What is an abstract class?

a class that is denoted by the class keyword (can be seen and used by any other class in the system–thus it is by default public)
something denoted by the abstract keyword and used system-wide; if you want any program to create an object of a class you use the abstract class
a class that is denoted by the virtual keyword
a class that can be used only as a base class✔

Official documentation: Abstract and Sealed Classes and Class Members

Q22. When using a thread pool what happens to a given thread after it finishes its task?

The thread is destroyed and memory is freed up.
The thread runs in a loop until the next assignment.
The thread goes inactive in the background and waits for garbage collection.
The thread returns to the pool for reuse.✔

Official documentation: Thread pool characteristics

Q23. Which choice represents a class that inherits behavior from a base class?

a second base class
a revised class
a derived class✔
a parent class

Official documentation: Inheritance

Q24. What does operator overloading allow you to do?

hide built-in operators when necessary
add methods to be interpreted by the compiler at runtime
define how enums and other primitive value types work within the rest of the application
define custom functionality for common operators like addition and equality✔

Official documentation: Operator overloading

Q25. What is the main purpose of LINQ?

to delete duplicate data
to bind namespaces and assemblies
to query and transform data✔
to connect assemblies

Official documentation: Language Integrated Query (LINQ) Overview

Q26. What is the correct syntax for a new generic list of strings named contacts?

public List contacts = new List();
public List(string names) contacts = new List(string names)();
var contacts = new List();✔
var contacts = new List(string);

Official documentation: List Class

Q27. What is the difference between throw exceptions and throw clauses?

Throw clauses fire only at runtime, while throw exceptions can fire at any time.
Throw exceptions overwrite the stack trace, while throw clauses retain the stack information.✔
Throw clauses overwrite the stack trace, while throw exceptions retain the stack information.
Throw exceptions fire only at runtime, while throw clauses can fire during compile time.

Official documentation: throw

Q28. When an asynchronous method is executed, the code runs but nothing happens other than a compiler warning. What is most likely causing the method to not return anything?

The return yield statement is missing at the end of the method.
The method is missing an await keyword in its body.✔
The wait keyword is missing from the end of the method.
The yield keyword is missing from the method.

Official documentation: Starting tasks concurrently

Q29. What are C# events?

system actions that communicate directly with the compiler at runtime
actions that execute when the code compiles, generating logs and test output
actions that generate notifications, which are sent to their registered listeners✔
user-only methods that send data to the application’s back end

Official documentation: Introduction to events

Q30. What kind of values can arrays store?

unordered collections of numeric values
key-value pairs of any C# supported type
class and struct instances
multiple variables, or collections, of the same type✔

Official documentation: Arrays

Q31. Given this enumeration, how would you access the integer-type value of ‘AppState.Loading’?

enum AppState { OffLine, Loading, Ready }

string currentState = (string)AppState.Loading;
string currentState = AppState.Loading.integralVal;
int currentState = AppState.Loading.rawValue;
int currentState = (int)AppState.Loading;✔

Official documentation: Enumeration types

Q32. What character would you use to start a regular expression pattern at a word boundary?

d
\a
\b✔
\w

Official documentation: Regular Expression Language – Quick Reference

Q33. To conform to the following interface, which of its members need to be implemented?

publicinterfaceINameable
{
    string FirstName { get; set; }
    string LastName { get; }
}
Code language: JavaScript (javascript)

Both the FirstName and LastName properties need to be implemented.✔
Neither, they are both optional.
Only the LastName property needs to be implemented.
Only the FirstName property needs to be implemented.

Official documentation: interface

Q34. You’re dealing with multiple assemblies in your program, but are worried about memory allocation. At what point in the program life cycle are assemblies loaded into memory?

at runtime
at compile time
only when required✔
only when programmatically loaded

Official documentation: Assembly Loading

Q35. What is the most accurate description of a regular expression?

A regular expression is a C# tool used to parse HTML
A regular expression is a special text string for describing a search pattern.✔
A regular expression allows a variable to be passed by reference.
A regular expression allows a class to conform to the Equatable protocol.

Q36. Why would you use a class field in C#

To define the behaviors of the class
To hold information and data contained in the class object✔
To communicate between classes and object
To store the class definition value

Official documentation: Introduction to classes

Q37. When would you use generics in your code?

to increase code performance
all of these answers✔
when code reuse is a priority
when type safety is important

Official documentation: Generic classes and methods

Q38. What prints to the console when this code is executed?

public delegate void AuthCallback(bool validUser);
publicstatic AuthCallback loginCallback = Login;
public static void Login()
{
    Console.WriteLine("Valid user!");
}

public static void Main(string[] args)
{
    loginCallback(true);
}
Code language: JavaScript (javascript)

Login successful…
Valid user!
an error, because the method signature of Login doesn’t match the delegate✔
Login successful… Valid user!

Q39. How would you declare a sealed class named User?

public class User {}
abstract User {}
sealed class User {}✔
private sealed class User {}

Official documentation: Abstract and Sealed Classes and Class Members

Q40. What is the difference between non-static and static classes?

non-static classes need to be initialized before use, while static classes do not✔
non-static classes are accessible only from an interface while static classes are accessible from anywhere
non-static classes need to initialize all class members at runtime, while static classes do not
non-static classes do not need to be initialized while static classes do

Official documentation: Static Constructors

Q41. Which characteristic prevents this code from compiling?

public int age=”28″

type safety✔
single inheritance
dependency injection
multiple inheritance

Q42. How would you serialize this class?

public class User {}

Mark the User class with the DeserializableAttribute.
Declare the class as public serializable class User {}.
Mark the User class with the SerializableAttribute attribute.✔
Declare the class as private serializable class User {}.

Official documentation: SerializableAttribute Class

Q43. How would you write a delegate named ResultCallback with an int parameter named responseCode?

public delegate ResultCallback(int responseCode);
public delegate void ResultCallback<(int) responseCode>;
public void delegate ResultCallback<int responseCode>;
public delegate void ResultCallback(int responseCode);✔

Official documentation: Delegates

Q44. What is the difference between a static and non-static method?

non-static methods always need to have a void return type
non-static methods do not have access to static member variables
static methods do not have to instantiate an instance of the class to call the method✔
static methods always have to be public

Official documentation: Static Members

Q45. What is the correct way to write an event named apiResult based on a delegate named ResultCallback?

public void event ResultCallback apiResult;
public event ResultCallback(() -> apiResult);
public event void ResultCallback
public event ResultCallback apiResult;✔

Official documentation: Introduction to events

Q46. When will the code inside finally block be executed in a try-catch statement?

if there is an error, it won’t execute at all
between the try and catch blocks
after the try and catch blocks✔
when the finally block overrides the catch block and executes in its place

Official documentation: try-catch

Q47. What method correctly extends the string class?

public static string IsvalidName(this string i, string value) {}✔
public static void IsvalidName(this string i, string value) {}
public string IsvalidName(this string i, string value) {}
public void IsvalidName(this string i, string value) {}

Q48. How are C# classes limited?

They do not support multiple inheritance.✔
They support multiple inheritance.
They can have only a set number of properties.
They can have only a set number of methods.

Official documentation: Class inheritance

Q49. What function do namespaces perform?

Namespaces calculate code coverage at runtime.
Namespaces compile application code together at compile time.
Namespaces group code together into a single repository.
Namespaces separate code into groupings, control access, and avoid naming collisions.✔

Official documentation: namespace

Q50. What is the correct way to write a public property with a private backing field?

privateint _password;
pubic int Password = { get; set; }
Code language: JavaScript (javascript)

privateint _password;
publicint Password = _password;

privateint _password;
publicint Password
{
  get -> _password;
  set-> _password = value;
}
Code language: JavaScript (javascript)

D✔

privateint _password;
publicint Password
{
  get { return _password; }
  set { _password = value; }
}
Code language: JavaScript (javascript)

Official documentation: Using Properties

Q51. What is a thread pool?

a collection of synchronous methods created during initialization that cannot be reused
a collection of threads created during initialization that can be reused✔
a collection of threads only recognized at compile time that can be reused
a collection of asynchronous methods created at compile time that cannot be reused

Official documentation: ThreadPool Class

Q52. When an object in C# is serialized, what is it converted to?

XML
JSON
byte stream✔
value stream

Official documentation: Serialization

Q53. What is a delegate

a variable that holds a reference to a value type and its content
a specific value type that can be used only in callback methods
a type that holds a reference to a method with a particular parameter list and return type✔
a custom variable type that can be used in abstract classes

Official documentation: Delegates

Q54. What are the four keywords associated with exception handling in C#?

try, catch, valid, invalid
try, valid, finally, throw
try, catch, finally, throw✔
finally, throw, valid, invalid

Q55. What is the main difference between the is and as operators?

The is operator checks instance types, while the as operator checks the inherited type.
The is operator checks primitive data types, while the as operator checks the object type.
The as operator checks the object type, while the is operator attempts to cast an object to a specific type.
The is operator checks the object type, while the as operator attempts to cast an object to a specific type.✔

Q56. What is the difference between finally and finalize blocks?

The finally block is called during the execution of a try and catch block, while the finalize method is called after garbage collection.
The finally block is called after the execution of a try and catch block, while the finalize method is called just before garbage collection.✔
The finalize block is called before the execution of a try and catch block, while the finally method is called just before garbage collection.
The finalize block is called during the execution of a try and catch block, while the finally method is called after garbage collection.

Q57. Your application has a value type called username that needs to be able to accept null values, but this is generating compile-time errors. How would you fix this in code?

Null username = null;
string? username = null;✔
Type? username = null;
Optional username = null;

Q58. Which code snippet correctly declares a custom exception named InvalidResponse?

struct InvalidResponse: Exception {}
class InvalidResponse: Exception {}✔
public Exception InvalidResponse = new Exception ();
public Exception InvalidResponse () -> Exception;

Official documentation: Exceptions

Q59. How would you write an enum variable called AppState with values for Offline, Loading, and Ready?

enum AppState = [Offline, Loading, Ready]
enum AppState {“Offline”, “Loading”, “Ready”}
enum AppState = {Offline, Loading, Ready}
enum AppState {Offline, Loading, Ready}✔

Official documentation: Enum

Q60. What is the main difference between a value type and a reference type?

A value type can be any primitive type, while reference types must be type-agnostic.
A value type refers to another value, while a reference type refers to a value in memory.
A value type stores an actual value, while a reference type is a pointer to a value.✔
A value type is available only at runtime, while a reference type is available only at compile time.

Q61. What is the difference between the break and continue keywords?

The break keyword is used to break out of multiple iteration statements, while continue can only break out of code blocks that have single iterations.
The break keyword literally breaks out of a control flow statement, while continue ignores the rest of the control statement or iteration and starts the next one.✔
The break keyword literally breaks out of the current control flow code and stops it dead, while continue keeps executing the code after an exception is thrown.
The break keyword jumps out of an iteration and then proceeds with the rest of the control flow code, while continue stops the executing code dead.

Official documentation: Jump statements

Q62. Which code snippet correctly declares a variable named userId with a public get and private set?

public int userID <get, set>;
public int userID [get, private set];
public int userID { get; private set; }✔
public int userID = { public get, private set };

Official documentation: Properties

Q63. What is true about virtual methods?

Overriding virtual methods in a derived class is mandatory.
Overriding virtual methods in a derived class is not possible.
Virtual methods always need a default implementation.✔
Virtual methods cannot have a default implementation.

Official documentation: virtual

Q64. What is likely to happen if you have multiple threads accessing the same resource in your program?

resource overload
thread jumping
deadlock and race conditions✔
nothing, since this is what threading is for

Official documentation: race conditions

Q65. How do you indicate that a string might be null?

A string cannot be nullable.
string? myVariable✔
string myVariable = null
string(null) myVariable

Official documentation: nullable value types

Q66. Do you need to declare an out variable before you use it?

No, you can declare an out in the parameter list.✔
No, Out variables are no longer part of C#.
You must declare it if it is a primitive type.
Yes.

Q67. How would you access the last two people in an array named People?

People[..^2]✔
You cannot do this in C#.
People[..^3]
People[^2]

Official Documentation: Ranges

Q68. When can anonymous types be created?

at compile time✔
after runtime
at runtime
after compile time

Q69. What is true about thread multitasking?

Thread multitasking allows code to be executed concurrently✔
Thread multitasking allows code to be executed only when handling a user event.
Thread multitasking blocks code from being executed simultaneously to guard memory.
Thread multitasking adds single-threaded code blocks together.

Official Documentation: Threads

Q70. What accessibility level does this class field have?

private string LastName;

It can be used by other code only in the same class or struct.✔
It can be used by other code in a referenced assembly.
It can be used only by code contained in a derived class.
It can be used by other code in the same assembly.

Official Documentation: Accessibility Levels

Q71. How would you correctly declare a jagged array called ‘partyInvites’ with 10 empty elements?

string[] partyInvites = new string[10];
string[][] partyInvites = new string[10][];✔
string[][] partyInvites = new string[10]();
string <[]> partyInvites = new string <[10]>;

Official Documentation: Jagged Arrays

Q72. How could you pause a thread for three seconds?

Thread.Pause(3000);
Thread.Resume(-3000);
Thread.Suspend(3000);
Thread.Sleep(3000);✔

Reference

Q73. What is wrong with this code?

void MyFunction()
{
    {
        int a = 10;
        int b = 20;
        int c = a + b;
    }

    Console.WriteLine(c);
}
Code language: JavaScript (javascript)

Variable c is never used; displaying it on the console does not count as usage.
Variables a and b are never used.
You cannot place code inside brackets inside another block.
Variable c no longer exists outside the block.✔

Q74. Which statement is True?

All are true.
None are true.
string is a value type.
string is an alias for String✔

Q75. How would you return more than one value from a method?

Use either a tuple or an out variable.✔
The only way is to use an out variable.
The only way is to use a tuple.
This cannot be done

Q76. Which is a valid example of a derived class?

public class PremiumUser sub User {}
public class PremiumUser: User {}✔
public class PremiumUser -> sub User {}
public class User: PremiumUser {}

Q77. What is the correct way to call a static method named DebugString from a static class called InputManager?

static InputManager.DebugString();
InputManager().DebugString;
new InputManager().DebugString();
InputManager.DebugString();✔

Q78. What values can be assigned to this variable?

publicstring? nickname

null
String values
String values or null✔
String values with more than one character

Q79. What is a destructor?

a special called automatically whenever an object is created or updated
an implicit method called automatically when thread pools are processed concurrently
an explicit method called automatically when the compiler starts running
a special method called automatically whenever an object is deleted or destroyed✔

Reference

Q80. Which code snippet correctly declares a CustomInt type alias of type Int32?

typealias CustomInt = System.Int32;
var<T> CustomInt = Int32;
using CustomInt = System.Int32;✔
type CustomInt = System<Int32>;

Reference

Q81. What is an enumeration type?

an object of pass by reference type
a value type that cannot hold constants
set of named integral constants✔
an object of pass-by-value type

Q82. What is the readonly keyword used for in-field declarations?

to declare a member variable that cannot be calculated at runtime
to declare a field whose value can be assigned only before the constructor exits✔
to declare a static variable that must be set at compile time
to declare a static variable that must be set at runtime

Q83. Which statement is true of C# methods?

Methods store variables.
Methods are actions that an object can take✔
A method can be used only once per C# file.
A method determines the state of a given property.

Official documentation: Methods (C# Programming Guide)

Q84 Which is a valid built-in C# Exception class?

ArgumentNullValue
InvalidFormatFoundException
IndexOutOfPocket
ArgumentNullException✔

Official documentation: ArgumentNullException Class

Q85. What is the purpose of an interface in C#?

Interfaces are used to store data.
Interfaces define a contract that classes must adhere to, specifying a set of methods and properties that implementing classes must provide.✔
Interfaces are used to create instances of classes.
Interfaces are used for code organization.

Official Documentation: Interfaces (C# Programming Guide)

Q86. What is the primary purpose of the finally block in a C# try-catch-finally statement?

The finally block is used to handle exceptions.
The finally block is used to define the main logic of the try-catch statement.
The finally block is optional and not required in try-catch statements.
The finally block is used to ensure that certain code is executed regardless of whether an exception occurs.✔

Official Documentation: try-catch (C# Reference)

Q87. Which data structure in C# allows you to store key-value pairs and is often used for quick data retrieval?

ArrayList
List
Array
Dictionary✔

Official Documentation: Dictionary Class

Q88 The execution of the program begins with?

Main()✔
Get()
Class()
Display()

Q89 In C# ‘using’ is a?

Class
Directive✔
Function
Keyword