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

1. What is the primary benefit of using the 'async' and 'await' keywords in C#?

They improve code readability.

They allow code to run faster.

They simplify handling asynchronous operations and avoid blocking the main thread.

They enable multi-threading in C# applications.

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

create

new

instance

instantiate

3. 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#.

4. What does C# stand for?

C Sharp

C Plus

C Hash

C Number

5. 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.

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

bool

int

double

string

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

constructor() { }

init() { }

void constructor() { }

public ClassName() { }

8. 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#.

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

10. What is the purpose of the 'using' statement in C#?

To include external libraries

To declare variables

To define classes

To create objects

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

int

double

string

array

12. 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.

13. What is 'dependency injection' in C#?

A technique for injecting errors into code for testing purposes.

A method for injecting database queries into code for performance optimization.

A design pattern that allows objects to receive their dependencies from an external source rather than creating them internally.

A way to inject external libraries into a C# application.

14. 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

15. What is the default access modifier for class members in C# if no access modifier is specified?

public

private

protected

internal

16. What is the purpose of 'extension methods' in C#?

To extend the duration of method execution.

To add new methods to existing types without modifying their source code.

To optimize the performance of methods in C#.

To create methods with variable numbers of parameters.

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

const myVar = 10;

constant myVar = 10;

final myVar = 10;

var constant myVar = 10;

18. Which C# data type is used to store decimal numbers with high precision?

int

double

decimal

float

19. What is the primary purpose of the 'using' statement in C#?

To define a new variable

To import namespaces

To create a loop

To declare a constant

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

main()

start()

entry()

Main()

21. What is 'serialization' in C#?

A process for generating random numbers in C#.

A technique for sorting arrays in C#.

A mechanism for converting an object into a stream of bytes for storage or transmission.

A way to optimize database queries in C#.

22. 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#.

23. How do you declare a variable in C#?

var myVar = 10;

int myVar = 10;

float myVar;

string myVar = 'Hello';

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

new myClass();

create myClass();

instantiate myClass();

instance myClass();

25. Which C# keyword is used to define an enumeration?

enum

class

struct

interface

26. 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#.

27. 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

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

const

constant

var

readonly

29. What is 'polymorphism' in C#?

A technique for encrypting data in C#.

A design principle that allows objects of different types to be treated as objects of a common base type.

A method for overloading operators in C#.

A way to define multiple constructors in a class.

30. 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

C# MCQ Test 3