Ultimate C Sharp Test - 79+ MCQs: C# test: Evaluate Your Skills with C# Questions and Answers

1. What is the purpose of the 'using' directive in C#?

It is used to define custom namespaces.

It is used to declare variables.

It is used to include external libraries and namespaces.

It is used to specify access modifiers for class members.

2. What is 'tuple' in C#?

A data structure that stores a single value.

A type of exception in C#.

A collection of key-value pairs.

An ordered collection of elements with a specific type.

3. What is 'asynchronous programming' in C#?

A technique for running code sequentially.

A method for executing code in parallel.

A way to write code that can perform non-blocking operations and continue executing other tasks.

A way to optimize database queries in C#.

4. In C#, what is the purpose of the 'using' statement?

It is used for declaring variables.

It defines a namespace for a class.

It ensures that resources are properly disposed of when no longer needed.

It specifies access modifiers for class members.

5. How do you define a constant value in C#?

const myValue = 10;

constant myValue = 10;

var myValue = 10;

readonly myValue = 10;

6. What is the purpose of the 'try', 'catch', and 'finally' blocks in C#?

To define loops

To declare variables

To handle exceptions

To create conditions

7. What is the purpose of the 'base' keyword in C#?

It is used to access the base class's constructor.

It is used to define a base class for inheritance.

It is used to access the base class's static members.

It is used to specify access modifiers for class members.

8. How do you define a property in a C# class?

property myProperty { get; set; }

int myProperty { }

function myProperty() { }

var myProperty = 10;

9. What is 'boxing' and 'unboxing' in C#?

Boxing is the process of converting a value type to a reference type, and unboxing is the reverse operation.

Boxing is the process of converting a reference type to a value type, and unboxing is the reverse operation.

Boxing and unboxing are techniques for optimizing memory usage in C#.

Boxing and unboxing are used for handling exceptions in C#.

10. What is the C# operator for multiplication?

11. What is the C# syntax for creating a new instance of a class?

new myClass();

create myClass();

instantiate myClass();

instance myClass();

12. What is 'method overloading' in C#?

A way to override base class methods.

A technique for creating methods with the same name but different parameters in the same class.

A method for calling methods from another class.

A way to define custom operators in C#.

13. In C#, which type of loop is best suited for iterating over arrays and collections?

for loop

while loop

do-while loop

switch loop

14. What is the C# operator for logical AND?

15. Which C# data type is used to represent true or false values?

bool

int

double

string

16. Which C# operator is used to perform logical AND between two Boolean values?

17. What is the purpose of the 'this' keyword in C#?

To create a new instance of a class

To reference the current instance of a class

To declare a constant

To define a new variable

18. In C#, what keyword is used to define a constant?

const

constant

var

readonly

19. Which C# keyword is used to indicate that a class cannot be inherited from?

inherit

final

sealed

abstract

20. In C#, what keyword is used to define a class?

class

define

struct

new

21. In C#, what is the purpose of the 'StringBuilder' class?

To define variables

To build strings efficiently

To create loops

To perform mathematical operations

22. In C#, what keyword is used to create an array?

array

new

create

list

23. Which of the following is a reference type in C#?

int

double

string

array

24. How do you define a constructor in a C# class?

constructor() { }

init() { }

void constructor() { }

public ClassName() { }

25. What is the default access modifier for class members in C#?

public

private

protected

internal

26. What is a 'delegate' in C#?

A pointer to a function.

A reference to a class instance.

A collection of key-value pairs.

A keyword for declaring variables.

27. What is the purpose of the 'yield' keyword in C#?

It indicates a variable is read-only.

It defines an iterator method, allowing it to yield values one at a time.

It specifies that a method should be executed asynchronously.

It declares a variable that will be lazily initialized.

28. What is the syntax for a single-line comment in C#?

// This is a comment

# This is a comment

-- This is a comment

/* This is a comment */

29. What is the purpose of the 'using' statement in C# when working with resources like files or database connections?

To declare a variable

To import namespaces

To create an object

To ensure proper resource cleanup

30. Which keyword is used to define a class in C#?

function

class

method

interface

31. What is the purpose of the 'is' keyword in C#?

To perform arithmetic operations

To check the type of an object

To define a new variable

To create an array

32. Which C# keyword is used to handle exceptions?

try

catch

throw

exception

33. Which C# keyword is used to indicate that a method can be overridden in a derived class?

override

virtual

abstract

sealed

34. What is the entry point of a C# program?

main()

start()

entry()

Main()

35. Which C# data type is used to store a single character?

char

string

character

letter

36. What is 'attribute-based programming' in C#?

A technique for hiding code from external access.

A method for obfuscating code in C#.

A way to define custom attributes and apply them to code elements for additional metadata and behavior.

A way to define classes with attributes instead of methods.

37. What is the purpose of the 'volatile' keyword in C#?

It indicates that a variable cannot be modified.

It specifies a variable's data type.

It ensures that variable access is synchronized between multiple threads.

It defines a constant value.

38. In C#, how do you declare a constant variable?

const myVar = 10;

constant myVar = 10;

final myVar = 10;

var constant myVar = 10;

39. What is the purpose of 'interface' in C#?

To define a contract that classes must implement.

To specify the access modifiers for class members.

To define a base class for inheritance.

To define namespaces in C#.

40. Which C# keyword is used to exit a method without returning a value?

break

return

exit

continue

41. What is the purpose of the 'foreach' loop in C#?

To define a new variable

To iterate over elements of a collection

To create an infinite loop

To execute code once

42. What keyword is used to define a method that does not return any value in C#?

void

null

none

empty

43. What is 'LINQ' in C#?

A programming language for developing Windows applications.

A query language for querying databases in C#.

A tool for drawing user interfaces in C#.

A way to declare variables in C#.

44. What is the difference between 'ref' and 'out' parameters in C#?

'ref' parameters are passed by reference and must be initialized before being passed to a method, while 'out' parameters are also passed by reference but can be uninitialized.

'ref' parameters are passed by value and must be initialized before being passed to a method, while 'out' parameters are passed by reference.

'ref' parameters are used for value types, while 'out' parameters are used for reference types.

There is no difference between 'ref' and 'out' parameters in C#.

45. What is the purpose of the 'finally' block in a try-catch-finally statement?

To catch exceptions

To handle errors

To execute code regardless of whether an exception is thrown or not

To define variables

46. Which C# keyword is used to define a new instance of a class?

new

instance

create

instantiate

47. In C#, what keyword is used to create an instance of a class?

create

new

instance

instantiate

48. Which C# keyword is used to exit a loop prematurely?

break

continue

return

exit

49. What is the purpose of the 'using' directive in a C# program?

To declare variables

To define classes

To import namespaces

To create objects

50. What is the difference between 'sealed' and 'abstract' classes in C#?

'sealed' classes cannot be inherited, while 'abstract' classes are meant to be inherited and cannot be instantiated.

'sealed' classes are meant to be inherited and cannot be instantiated, while 'abstract' classes cannot be inherited.

'sealed' classes and 'abstract' classes are the same in C#.

There is no such thing as 'sealed' or 'abstract' classes in C#.

C# MCQ Test 1