Prime 85 C# Interview Questions and Solutions for 2024

C# Interview Questions

Now, allow us to check out the highest C# interview questions that you just may face!

1. What’s C#?

C# is an object-oriented programming language compiled by the .Internet framework to generate Microsoft Intermediate Language.

Can a number of catch blocks be executed?

No, you can’t execute a number of catch blocks of the identical kind.

2. What’s the distinction between static, public, and void?

Public declared variables might be accessed from wherever within the software. Static declared variables might be accessed globally while not having to create an occasion of the category. Void is a sort modifier which states the strategy and is used to specify the return kind of a technique in C#.

3. What’s an object?

An object is a category occasion that can be utilized to entry class strategies. The “New” key phrase can be utilized to assemble an object.

4. Outline Constructors.

A constructor is a member operate with the identical identify as its class. The constructor is routinely invoked when an object is created. Whereas the category is being initialized, it constructs all of the values of knowledge members.

5. What are Jagged Arrays?

The Array which contains parts of kind array known as Jagged Array. The weather in Jagged Arrays might be of assorted dimensions and sizes.

6. What’s the distinction between out and ref parameters?

When an argument is handed as a ref, it should be initialized earlier than it may be handed to the strategy. An out parameter, alternatively, want to not be initialized earlier than passing to a technique.

7. What’s the advantage of ‘utilizing’ assertion in C#?

The ‘utilizing’ assertion can be utilized with a view to acquire a useful resource for processing earlier than routinely disposing it when execution is accomplished.

8. What’s serialization?

With the intention to transport an object by way of a community, we would want to transform it right into a stream of bytes. This course of known as Serialization.

9. Can “this” command be used inside a static technique?

No. It’s because solely static variables/strategies can be utilized in a static technique.

10. Differentiate between Break and Proceed Assertion.

Proceed assertion – Utilized in leaping over a selected iteration and stepping into the subsequent iteration of the loop.

Break assertion – Used to skip the subsequent statements of the present iteration and are available out of the loop.

11. Checklist the several types of feedback in C#.

The several types of feedback in C# are:

Instance –

/// instance of XML remark

Instance –

// instance of single-line remark

Instance –

/* instance of an

multiline remark */

12. Clarify the 4 steps concerned within the C# code compilation.

4 steps of code compilation in C# embody –

• Supply code compilation in managed code.
• Newly created code is clubbed with meeting code.
• The Widespread Language Runtime (CLR) is loaded.
• Meeting execution is completed by way of CLR.

13. Talk about the varied strategies to go parameters in a technique.

The varied strategies of passing parameters in a technique embody –

• Output parameters: Lets the strategy return multiple worth.
• Worth parameters: The formal worth copies and shops the worth of the particular argument, which allows the manipulation of the formal parameter with out affecting the worth of the particular parameter.
• Reference parameters: The reminiscence handle of the particular parameter is saved within the formal argument, which suggests any change to the formal parameter would replicate on the precise argument too.

14. Identify all of the C# entry modifiers.

The C# entry modifiers are –

• Personal Entry Modifier – A personal attribute or technique is one that may solely be accessed from throughout the class.
• Public Entry Modifier – When an attribute or technique is said public, it may be accessed from wherever within the code.
• Inside Entry Modifier – When a property or technique is outlined as inner, it will possibly solely be accessible from the present meeting level of that class.
• Protected Entry Modifier – When a consumer declares a technique or attribute as protected, it will possibly solely be accessed by members of that class and people who inherit it.

15. Point out all the benefits of C#.

The next are the benefits of C# –

• C# is component-oriented.
• It’s an object-oriented language.
• The syntax is very easy to understand.
• It’s simpler to study.
• C# is a part of the framework known as .NET

16. Point out the essential IDEs for C# improvement supplied by Microsoft.

The next IDEs’ are helpful in C# improvement –

• MonoDevelop
• Visible Studio Code (VS Code)
• Browxy
• Visible Studio Categorical (VSE)
• Visible Internet Developer (VWD)

17. Why will we use C# language?

Beneath are the the explanation why we use the C# language –

• C# is a component-oriented language.
• It’s simple to go parameters within the C# language.
• The C# language might be compiled on many platforms.
• The C# language follows a structured method.
• It’s simple to study and decide up.
• The C# language produces actually environment friendly and readable programmes.

18. Point out the options of C# briefly.

A number of the fundamental options of C# are –

• C# is a safely typed and managed language.
• C# is object-oriented in nature.
• C# is a Cross-platform pleasant language.
• C# is a platform-independent language in relation to compilation.
• C# is normal function in nature.
• C# is utilized in implementing Destructors and Constructors.
• C# is a part of the .NET framework.
• C# is an easy-to-learn and easy-to-grasp language.
• C# is a structured language.

19. What is supposed by Unmanaged or Managed Code?

In easy phrases, managed code is code that’s executed by the CLR (widespread language Runtime). Which means each software code is completely dependent on the .NET platform and is thought to be overseen in light of it. Code executed by a runtime programme that’s not a part of the .NET platform is taken into account unmanaged code. Reminiscence, safety, and different actions associated to execution will probably be dealt with by the appliance’s runtime.

20. What is supposed by an Summary Class?

It is a kind of sophistication whose objects cannot be instantiated, and it is signified by the time period ‘summary’. It consists of a technique or a single method.

21. Differentiate between finalize blocks and finalize.

As soon as the try to catch blocks have been accomplished, the finalize block known as since it’s used for exception dealing with. Regardless of if the exception has been captured, this block of code is run. Generally, the code on this block is cleaner.

Simply earlier than rubbish assortment, the finalize technique known as. The primary priorities of the finalize technique are to wash up unmanaged code, which is routinely triggered at any time when an occasion will not be re-called.

22. What is supposed by an Interface?

An interface is a category that doesn’t have any implementation. Solely the declarations of occasions, properties, and attributes are included.

23. What is supposed by a Partial Class?

A partial class successfully breaks a category’s definition into varied courses in the identical or different supply code information. A category definition might be written in quite a few information, however it’s compiled as a single class at runtime, and when a category is shaped, all strategies from all supply information might be accessed utilizing the identical object. The key phrase ‘partial’ denotes this.

24. What’s the distinction between read-only and constants?

Through the time of compilation, fixed variables are declared in addition to initialized. It’s not doable to vary this specific worth later. However, read-only is used after a price is assigned at run time.

25. What’s an interface class?

An interface class is an summary class with solely public summary strategies. Solely declaration is there in these strategies, however not the definition. They should be applied within the inherited courses.

26. What are reference sorts and worth sorts?

A worth kind holds an information worth inside its reminiscence area. Reference kind, alternatively, retains the article’s handle the place the worth is saved. It’s, basically, a pointer to a distinct reminiscence location.

27. What are Consumer Management and Customized Management?

Customized Controls are produced as compiled code. These are simple to make use of and might be added to the toolbox. Builders can drag and drop these controls onto their internet varieties. Consumer Controls are virtually the identical as ASP embody information. They’re additionally simple to create. Consumer controls, nonetheless, can’t be put within the toolbox. In addition they can’t be dragged and dropped from it.

28. What are sealed courses in C#?

When a restriction must be positioned on the category that must be inherited, sealed courses are created. With the intention to forestall any derivation from a category, a sealed modifier is used. Compile-time error happens when a sealed class is forcefully specified as a base class.

29. What’s technique overloading?

Technique overloading is the method of producing many strategies in the identical class with the identical identify however distinct signatures. The compiler makes use of overload decision to determine which technique to invoke once we compile.

30. What’s the distinction between Arraylist and Array?

An array solely has gadgets of the identical kind and its dimension if fastened. Arraylist is comparable however it doesn’t have a set dimension.

31. Is it doable for a non-public digital technique to be overridden?

A personal digital technique can’t be overridden as it will possibly’t be accessed outdoors the category.

32. Describe the accessibility modifier “protected inner”.

Variables or strategies which might be Protected Inside might be accessed throughout the similar meeting in addition to from the courses which have been derived from the father or mother class.

33. What are the variations between System.String and System.Textual content.StringBuilder courses?

System.String is absolute. When a string variable’s worth is modified, a brand new reminiscence is assigned to the brand new worth. The earlier reminiscence allocation will get launched. System.StringBuilder, alternatively, is designed so it will possibly have a mutable string by which a plethora of operations might be carried out with out the necessity for allocation of a separate reminiscence location for the string that has been modified.

34. What’s the distinction between the System.Array.CopyTo() and System.Array.Clone() ?

Within the Clone() technique, a brand new array object is created, with all the unique Array parts utilizing the CopyTo() technique. Primarily, all the weather current within the present array get copied into one other present array.

35. How can the Array parts be sorted in descending order?

You should use the Utilizing Kind() strategies after which Reverse() technique.

36. What’s the distinction between an summary and interface class?

All strategies in interfaces have solely a declaration however no definition. We will have some robust strategies in an summary class. All strategies in an interface class are public. Personal strategies might exist in an summary class.

37. What’s the distinction between Dispose() and Finalize()strategies?

Dispose() is used when an object is required to launch any unmanaged assets in it. Finalize(), alternatively, doesn’t guarantee the rubbish assortment of an object though it’s used for a similar operate.

38. What are round references?

When two or extra assets are depending on every, it causes a lock situation, and the assets turn out to be unusable. That is known as a round reference.

39. What are generics in C# .NET?

With the intention to cut back code redundancy, elevate kind security, and efficiency, generics can be utilized with a view to make code courses that may be reused. Assortment courses might be created utilizing generics.

40. What’s an object pool in .NET?

A container that has objects that are prepared for use is named an object pool. It helps in monitoring the article which is at present in use and the overall variety of objects current within the pool. This brings down the necessity for creating and re-creating objects.

41. Checklist down essentially the most generally used forms of exceptions in .NET

Generally used forms of exceptions in .NET are:

ArgumentException

ArithmeticException

DivideByZeroException

OverflowException

InvalidCastException

InvalidOperationException

NullReferenceException

OutOfMemoryException

StackOverflowException

42. What are Customized Exceptions?

In some instances, errors need to be dealt with in response to consumer necessities. Customized exceptions are utilized in such instances.

43. What are delegates?

Delegates are basically the identical as operate pointers in C++. The primary and solely distinction between the 2 is delegates are kind secure whereas operate pointers usually are not. Delegates are important as a result of they permit for the creation of generic type-safe features.

44. What’s the distinction between technique overriding and technique overloading?

In technique overriding, the related technique definition is changed within the derived class, which adjustments the strategy conduct. Relating to technique overloading, a technique is created with the identical identify and is in the identical class whereas having completely different signatures.

45. How do you inherit a category into one other class in C#?

In C#, colon can be utilized as an inheritance operator. You must place a colon and comply with it with the category identify.

46. What are the varied ways in which a technique might be overloaded??

Totally different knowledge sorts can be utilized for a parameter to ensure that a technique to be overloaded; completely different orders of parameters in addition to completely different numbers of parameters can be utilized.

47. Why cannot the accessibility modifier be specified for strategies throughout the interface?

In an interface, there are digital strategies which don’t include technique definition. All of the strategies current are to be overridden within the derived class. That is the explanation they’re all public.

48. How can we set the category to be inherited, however forestall the strategy from being overridden?

To set the category to be inherited, it must be declared as public. The strategy must be sealed to stop any overrides.

49. What occurs if the strategy names within the inherited interfaces battle?

An issue may come up when the strategies from varied interfaces anticipate completely different knowledge. However in relation to the compiler itself, there shouldn’t be a problem.

50. What’s the distinction between a Struct and a Class?

Structs are basically value-type variables, whereas courses could be reference sorts.

51. Methods to use nullable sorts in .Internet?

When both regular values or a null worth might be taken by worth sorts, they’re known as nullable sorts.

52. How can we make an array with non-standard values?

An array with non-default values might be created utilizing Enumerable.Repeat.

53. What’s the distinction between “is” and “as” operators in c#?

An “is” operator can be utilized to examine an object’s compatibility with respect to a given kind, and the result’s returned as a Boolean. An “as” operator can be utilized for casting an object to both a sort or a category.

54. What’s a multicast delegate?

Multicast delegate is when a single delegate comes with a number of handlers. Every handler is assigned to a technique.

55. What are indexers in C# .NET?

In C#, indexers are known as good arrays. Indexers permit class situations to be listed in the identical method as arrays do.

56. What’s the distinction between “throw” and “throw ex” in.NET?

“Throw” assertion retains the unique error stack. However “throw ex” retains the stack hint from their throw level.

57. What are C# attributes and its significance?

C# offers builders an choice to outline declarative tags on a couple of entities. As an example, class and technique are generally known as attributes. The knowledge associated to the attribute might be retrieved throughout runtime by taking the assistance of Reflection.

58. In C#, how do you implement the singleton design sample?

In a singleton sample, a category is allowed to have just one occasion, and an entry level is supplied to it globally.

59. What is the distinction between directcast and ctype?

If an object is required to have the run-time kind just like a distinct object, then DirectCast is used to transform it. When the conversion is between the expression in addition to the kind, then Ctype is used.

60. Is C# code managed or unmanaged code?

C# is a managed code because the runtime of Widespread language can compile C# code to Intermediate language.

61. What’s a Console software?

An software that is ready to run within the command immediate window known as a console software.

62. What are namespaces in C#?

Namespaces will let you hold one set of names that’s completely different from others. An awesome benefit of namespace is that class names declared in a single namespace don’t conflict with these declared in one other namespace.

63. What’s the distinction between the Dispose() and Finalize() strategies?

Namespaces, interfaces, constructions, and delegates can all be members.

64. Write options of Generics in C#?

Generics is a method to enhance your program in varied methods together with creating generic courses and reusing code.

65. Distinction between SortedList and SortedDictionary in C#.

SortedList is a group of worth pairs sorted by their keys. SortedDictionary is a group to retailer the worth pairs within the sorted kind, by which the sorting is completed on the important thing.

66. What’s Singleton design sample in C#?

Singleton design sample in C# has only one occasion that offers world entry to it.

67. What’s tuple in C#?

Tuple is an information construction to symbolize an information set that has a number of values that might be associated to one another.

68. What are Occasions?

An occasion is a discover that one thing has occurred.

69. What’s the Constructor Chaining in C#?

With Constructor Chaining, an overloaded constructor might be known as from one other constructor. The constructor should belong to the identical class.

70. What’s a multicasting delegate in C#?

Multicasting of delegates helps customers to level to multiple technique in a single name.

71. What are Accessibility Modifiers in C#?

Entry Modifiers are phrases that specify a program’s member, class, or datatype’s accessibility.

72. What’s a Digital Technique in C#?

Within the father or mother class, a digital technique is said that may be overridden within the little one class. We assemble a digital technique within the base class utilizing the digital key phrase, and that operate is overridden within the derived class with the Override key phrase.

73. What’s Multithreading with .NET?

Multi-threading refers to the usage of a number of threads inside a single course of. Every thread right here performs a distinct operate.

74. In C#, what’s a Hash desk class?

The Hash desk class represents a group of key/worth pairs which might be organized based mostly on the hash code of the important thing.

75. What’s LINQ in C#?

LINQ refers to Language Built-in Question. It offers .NET languages (like C#) the power to generate queries to retrieve knowledge from the information supply.

76. Why cannot a non-public digital process in C# be overridden?

Personal digital strategies usually are not accessible outdoors of the category.

77. What’s File Dealing with in C#?

File dealing with contains operations reminiscent of creating the file, studying from the file, and appending the file, amongst others.

78. What do you perceive about Get and Set Accessor properties?

In C#, Get and Set are termed accessors as a result of they use properties. Such personal fields are accessed through accessors.

79. What’s the Race situation in C#?

When 2 threads entry the identical useful resource and attempt to change it on the similar time, we’ve got a race situation.

80. Why are Async and Await utilized in C#?

Asynchronous programming processes execute independently of the first or different processes. Asynchronous strategies in C# are created utilizing the Async and Await key phrases.

81. What’s an Indexer in C#?

An indexer is a category property that lets you entry a member variable of one other class utilizing array traits.

82. What’s Thread Pooling in C#?

In C#, a Thread Pool is a bunch of threads. These threads are used to do work with out interfering with the principal thread’s operation.

83. What data are you able to present concerning the XSD file in C#?

XSD stands for XML Schema Definition. The XML file can have any attributes and parts if there isn’t any XSD file related to it.

84. What are I/O courses in C#?

In C#, the System.IO namespace incorporates a number of courses which might be used to conduct completely different file operations reminiscent of creation, deletion, closure, and opening.

85. What precisely do you imply by common expressions in C#?

An everyday expression is a sample that can be utilized to match a set of enter. Constructs, character literals, and operators are all doable.