C Sharp C# Linkedin Skill Test 2022 Updated Question Answers
1 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}
2.
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.
3.
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.
4.
Which code snippet correctly declares a variable names 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};
5.
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 default implementation.
6.
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
7. 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; }
}
8. Why would you use a class field
in C#
To
communicate between classes and object
To
define behaviours of the class
To
hold information and data contained in the class object
To
store the class definition value
9. When would you use generics in your
code?
when code reuse is a priority
when
type safety is important
to
increase code performance
all
of these answers
10. 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!
an
error, because the method signature of Login doesn't match the delegate
Login
successful... Valid user!
11. How would you declare a sealed class
named User?
abstract User {}
sealed
class User
private
sealed class User
public
class User
12. What is the correct way to write
an event named apiResult based on a delegate named ResultCallback?
public event void ResultCallback
public
event ResultCallback apiResult;
public
void event ResultCallback apiResult;
public event ResultCallback(()
-> apiResult);
13. When will the code inside
finally block be executed in a try-catch statement?
after the try and catch blocks
when
the finally block overrides the catch block and executes in its place
if
there is an error, it won't execute at all
between
the try and catch blocks
14. What method correctly extends the
string class?
public static void IsvalidName(this string i, string value) {}
public
string IsvalidName(this string i, string value) {}
public
static string IsvalidName(this string i, string value) {}
public
void IsvalidName(this string i, string value) {}
15. How are C# classses limited?
They support multiple inheritance.
They
can have only a set number of properties.
They
do not support multiple inheritance.
They
can have only a set number of methods.
16. What function do namespaces perform?
Namespaces
calculate code coverage at runtime.
Namespaces
separate code into groupings, control access, and void naming collisions.
Namespaces
compile application code together at compile time.
Namespaces
group code together into a single repository.
17. 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
18. When using a thread pool what
happens to a given thread after it finishes its task?
The
thread goes inactive in the background and waits for garbage collection.
The
thread returns to the pool for reuse.
The
thread is destroyed and memory is freed up.
The
thread runs in loop until the next assignment.
19. 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
20. 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
21. What does operator overloading
allow you to do?
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
hide
built-in operatores when necessary
add
methods to be interpreted by the compiler at runtime
22. What it the main purpose of
LINQ?
to
delete duplicate data
to
bind namespaces and assemblies
to
query and transform data
to
connect assemblies
23. 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);
24. What is the difference between
throw exceptions and throw clauses?
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.
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.
25. 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
wait keyword is missing from the end of the method.
The
yield keyword is missing from the method.
The
return yield statement is missing at the end of the method.
The
method is missing an await keyword in its body.
26. 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;
27. What are C# events?
system
actions that communicate directly with the compiler at runtime
actions
that generate notifications, which are sent to their registered listeners
user-only
methods that send data to the application's back end
actions
that execute when the code compiles, generating logs and test output
28. What kind of values can arrays
store?
unordered
collections of numerc values
multiple
variables, or collections, of the same type
key-value
pairs of any C# supported type
class
and struct instances
29. What is
the most accurate description of a regular expression?
A regular expressions allows a variable to be passed by reference
A regular expression allows a class to conform to the Equatable
protocol
A regular expression is a C# tool used to parse HTML
A
regular expression is a special text string for describing a search pattern
30. In which of these situations
are interfaces better than abstract classes?
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 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.
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.
31. Which statement is true of
delegates?
They
cannot be used as callbacks.
Delegates
are not supported in the current version of C#
Only
variables can be passed to delegates as parameters.
They
can be chained together.
32. Which choice best defines C#'s asynchronous
programming model?
inherited callback
task-based
Callback-based
reactive
33. 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)
Attribute.GetCustomAttribute(typeof(ExampleController),
typeof(SubControllerActionToViewDataAttribute))
34. What is the difference between
the ref and out keywords?
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.
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.
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.
35. How could you retrieve information
about a class, as well as create an instance at runtime?
abstraction
dependency
injection
reflection
serialization
36. 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) { }
}
}
thread
mismanagement
a
potential deadlock
a
private class that uses multithreading
multithread
coding
37. What is the difference between an
anonymous type and a regular data type?
Anonymous types can only be static
Anonymous
types can be used only in struts
Anonymous
types don't have type names
Anonymous
types don't work with LINQ.
38. When would you use a Dictionary
rather that an Array type in your application?
when you need to store key-value pairs rather than single values
when
you need an ordered, searchable list
when
you need a jagged collection structure
when
you need to store values of the same type
39. When an object in C# is serialized, what is it converted to?
XML
JSON
byte
stream
value stream
40. 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.
The is operator checks object
type, while the as operator attempts to cast an object to a specific type.
41. What is the difference between
a.Equals(b) and a == b?
The .Equals method compares contents while == compares references reference
identity.
The
.Equals method compares reference type while == compares primitive value types.
The
.Equals method compares reference identities while the == compares contents.
The
.Equals method compares primitive values while == compares all values.
42. 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
43. How does the async keyword work?
It allows the await keyword to be used in a method
It
allows access to synchronous methods in the C# API
It
allows access to asynchronous methods in the C# API
It
allows thread pooling and synchronous processes in static classes.
44. 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.
45. 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
46. 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
47. 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 };
48. What will be returned when
this method is executed?
public void
userInput(string charParamters) { }
a
string variable
an
integer
nothing
a
Boolean
49. 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);
}
first
in, first out
ascending
unordered
descending
50. Lambda expressions are often used in
tandem with which of the following?
Namespaces
LINQ
Type
Aliasing
Assemblies
51. What is the correct formatting for
single line and multiline comments?
// - Single Line / - Multiline
//
Multiline /_ Single Line _/
//*
Multiline / Single Line
//
Single Line /_ Multiline _/
52. How do you make a method in an
abstract class overridable?
Make it static
Make
it private
Make
it virtual
Make
it public
53. 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; }
54. Given this enumeration, how would
you access the integer-type value of 'AppState.Loading'?
enum AppState { OffLine,
Loading, Ready }
int
currentState = (int)AppState.Loading;
string
currentState = (string)AppState.Loading;
string
currentState = AppState.Loading.integralVal;
int
currentState = AppState.Loading.rawValue;
55. What character would you use
to start a regular expression pattern at a word boundary?
d
\a
\b
\w
56. To conform to the following
interface, which of its members need to be implemented?
public interface INameble
{
string
FirstName { get; set; }
string
LastName { get; }
}
Only
the LastName property needs to be implemented.
Only
the FirstName property needs to be implemented.
Both
the FirstName and LastName properties need to be implemented.
Neither,
they are both optional.
57. 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
58. What is the correct syntax for
a new generic list of strings named contacts?
public
List<string names> contacts = new List<string names>();
var
contacts = new List<string>();
var
contacts = new List(string);
public
List(string names) contacts = new List(string names);
59. What is the difference between
non-static and static classes?
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 need to be initialized before use, while static classes do not
non-static
classes do not need to be initialized while static classes do
60. Which characteristic prevents
this code from compiling?
public int
age="28"
type
safety
single
inheritance
dependency
injection
multiple
inheritance
61. How would you serialize this
class?
public
class User {}
Mark
the User class with the SerializableAttribute attribute.
Declare
the class as private serializable class User {}.
Mark
the User class with the DeserializableAttribute.
Declare
the class as public serializable class User {}.
62. 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
delegate void ResultCallback<(int) responseCode>;
public
void delegate ResultCallback;
63. What is the difference between
a static and non-static method?
static
methods do not have to instantiate an instance of the class to call the method
static
methods always have to be public
non-static
methods always need to have a void return type
non-static
methods do not have access to static member variables
64. In C#, a subroutine is called a
________.
Function
Metadata
Method
Managed
code
65. What is the Size of ‘Char’ datatype?
8 bit
12
bit
16
bit
20
bit
66. What will be the output of the
following C# code?
static void Main(string[] args)
{
string s1 =
"Delhi";
string s2;
s2 = s1.Insert (6,
"Jaipur");
Console.WriteLine(s2);
}
DelhJaipuri
Delhi
Jaipur
Delhi
DelhiJaipur
67. What is most
accurate description of a regular expression?
A
regular expression allows a class to conform to the equatable protocol.
A
regular expression is a C# tool used to parse HTML
A
regular expression is a special text string for describing a search patters.
A
regular expression allows a variable to be passed by reference.
68 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 can be used only as base class
a
class that is denoted by the virtual keyword
69. 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;
