LinkedIn C# (C Sharp) Assessment Answers 2023

LinkedIn C# (C Sharp) Assessment Answers 2023: C# (C Sharp) Skill Badge: C# (C Sharp) LinkedIn Test Answers: In this post you will get all the correct answers of LinkedIn C# (C Sharp) quiz answers given by the experts.

Note: Choose the correct answers marked with [x].

LinkedIn C# (C Sharp) Assessment Quiz Questions and Answers 2023

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.
[x] When you need a list of capabilities and data that are classes-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.
[x] They can be chained together.

Official documentation: Delegates

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

[ ] reactive
[ ] inherited callback
[x] 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>();

[ ] .

var typeof(MyPresentationModel).Should().BeDecoratedWith<SomeAttribute>();

[ ] .

Attribute.GetCustomAttribute, typeof(SubControllerActionToViewDataAttribute)

[x] .

Attribute.GetCustomAttribute(typeof(ExampleController), typeof(SubControllerActionToViewDataAttribute))

Official documentation: Attribute Class

Official documentation: Attribute.GetCustomAttribute Method

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

[ ] Variables passed to out 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.
[x] 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.

Official documentation: ref

Official documentation: out parameter modifier

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

[x] reflection
[ ] serialization
[ ] abstraction
[ ] dependency injection

Official documentation: Reflection

Q7. What is this code an example of?

    private static object objA;
    private static object objB;

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

    private static void PerformTaskB()
    {
        lock (objA)
        {
            lock (objB) { }
        }
    }

[ ] a private class that uses multithreading
[ ] multithread coding
[ ] thread mismanagement
[x] a potential deadlock

Official documentation: Deadlocks and race conditions

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

[x] 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 that an Array type in your application?

[ ] when you need a jagged collection structure
[ ] when you need to store values of the same type
[x] 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.
[x] The .Equals method compares contents while == compares references reference identity.
[ ] The .Equals method compares reference type while == compares primitive value types.

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
[x] 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.
[x] 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
[x] 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 };
[x] 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 charParamters) { }

[x] 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);
}

[x] ascending
[ ] unordered
[ ] descending
[ ] first in, first out

dotnetpattern: LINQ OrderBy Operator

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

[ ] Namespaces
[x] 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
[x] // Single Line
/_ Multiline _/

w3schools: C# Comments

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

[ ] Make it public
[ ] Make it static
[ ] Make it private
[x] Make it virtual

Official documentation: virtual

Official documentation: abstract

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 );
[x] 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
[x] a class that can be used only as 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 loop until the next assignment.
[ ] The thread goes inactive in the background and waits for garbage collection.
[x] 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
[x] a derived class
[ ] a parent class

Official documentation: Inheritance

Q24. What does operator overloading allow you to do?

[ ] hide built-in operatores 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
[x] define custom functionality for common operators like addition and equality

Official documentation: Operator overloading

Q25. What it the main purpose of LINQ?

[ ] to delete duplicate data
[ ] to bind namespaces and assemblies
[x] 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)();
[x] 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.
[x] 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

c-sharpcorner: Difference Between Throw Exception and Throw Clause

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.
[x] 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.

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
[x] 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 numerc values
[ ] key-value pairs of any C# supported type
[ ] class and struct instances
[x] 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;
[x] 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
[x] \b
[ ] \w

regular-expressions: Word Boundaries

Official documentation: Regular Expression Language – Quick Reference

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

public interface INameble
{
    string FirstName { get; set; }
    string LastName { get; }
}

[x] 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
[x] only when required
[ ] only when programmatically loaded

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

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

Official documentation: Regular Expression Language – Quick Reference

Official documentation: .NET regular expressions

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

[ ] To define behaviours of the class
[x] 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
[x] 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);
public static AuthCallback loginCallback = Login;
public static void Login()
{
    Console.WriteLine("Valid user!");
}

public static void Main(string[] args)
{
    loginCallback(true);
}

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

Official documentation: Introduction to Delegates

Official documentation: Introduction to Events

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

[ ] public class User {}
[ ] abstract User {}
[x] 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?

[x] 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

stackoverflow

Official documentation: Static Constructors

Q41. Which characteristic prevents this code from compiling?

public int age="28"

[x] type safety
[ ] single inheritance
[ ] dependency injection
[ ] multiple inheritance

c-sharpcorner: Type Safety in .NET

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 {}.
[x] 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\;
[x] 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
[x] 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
[x] 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
[x] 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?

[x] 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# classses limited?

[x] 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.
[x] Namespaces separate code into groupings, control access, and void naming collisions.

Official documentation: namespace

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

private int _password;
pubic int Password = { get; set; }

private int _password;
public int Password = _password;

private int _password;
public int Password
{
  get -> _password;
  set-> _password = value;
}

private int _password;
public int Password
{
  get { return _password; }
  set { _password = value; }
}

Official documentation: Using Properties

Q51. What is a thread pool?

[ ] a collection of synchronous methods created during initialization that cannot be reused
[x] 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
[x] 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
[x] 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
[x] try, catch, finally, throw
[ ] finally, throw, valid, invalid

Tutorial Point

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 object type, while the is operator attempts to cast an object to a specific type.
[x] The is operator checks object type, while the as operator attempts to cast an object to a specific type.

Pluralsight guide

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.
[x] 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.

C-sharpcorner

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;
[x] string? username = null;
[ ] Type? username = null;
[ ] Optional username = null;

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

[ ] struct InvalidResponse: Exception {}
[x] 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}
[x] 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.
[x] 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.

Official documentation: Value types

Official documentation: Reference types

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.
[x] 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];
[x] 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.
[x] Virtual methods always need a default implementation.
[ ] Virtual methods cannot have default implementation.

Official documentation: virtual

c-sharpcorner: Virtual Method in C#

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

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

[ ] A string cannot be nullable.
[x] string? myVariable
[ ] string myVariable = null
[ ] string(null) myVariable

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

[x] No, you can declare it in the parameter list.
[ ] 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?

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

Official Documentation: Ranges

Q68. When can anonymous types be created?

[x] at compile time
[ ] after runtime
[ ] at runtime
[ ] after compile time

C-sharpcorner: Anonymous Types

Q69. What is true about thread multitasking?

[x] 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;

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

Official Documentation: Jagged Arrays

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