Top 50+ C# Interview MCQS for 2024



  1. Which of the following is the correct syntax to declare a variable in C?

    A. int x;

    B. x int;

    C. int: x;

    D. int = x;

    Answer: A. int x;

 

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

    A. class

    B. define

    C. struct

    D. function

    Answer: A. class

 

 3. How do you create a new object in C?

    A. new ClassName();

    B. ClassName obj = new ClassName();

    C. ClassName obj = create ClassName();

    D. new ClassName obj;

    Answer: B. ClassName obj = new ClassName();

 

 4. Which of the following is the entry point of a C console application?

    A. Main()

    B. Start()

    C. Begin()

    D. Init()

    Answer: A. Main()

 

 5. How do you write a singleline comment in C?

    A. // comment

    B. / *comment* /

    C. <! comment >

    D.  comment

    Answer: A. // comment

 

 6. Which of the following is not a value type in C?

    A. int

    B. float

    C. bool

    D. string

    Answer: D. string

 

 7. How do you handle exceptions in C?

    A. try...catch

    B. try...except

    C. try...finally

    D. try...handle

    Answer: A. try...catch

 

 8. Which method is used to get the length of a string in C?

    A. str.size()

    B. str.length()

    C. str.Length

    D. str.getSize()

    Answer: C. str.Length

 

 9. Which keyword is used to inherit a class in C?

    A. inherits

    B. extends

    C. implements

    D. :

    Answer: D. :

 

 10. How do you define a constant in C?

    A. const int x = 10;

    B. define int x = 10;

    C. static int x = 10;

    D. final int x = 10;

    Answer: A. const int x = 10;

 

 11. Which of the following access specifiers is the most restrictive?

    A. public

    B. protected

    C. private

    D. internal

    Answer: C. private

 

 12. What is the default value of an uninitialized int variable in C?

    A. null

    B. 0

    C. 1

    D. undefined

    Answer: B. 0

 

 13. How do you declare an array in C?

    A. int[] arr;

    B. int arr[];

    C. array int arr;

    D. int arr{};

    Answer: A. int[] arr;

 

 14. Which keyword is used to define an interface in C?

    A. class

    B. interface

    C. implements

    D. abstract

    Answer: B. interface

 

 15. What does the static keyword mean in C?

    A. The method or variable belongs to the class itself.

    B. The method or variable cannot be changed.

    C. The method or variable is inherited.

    D. The method or variable is accessible only within its own class.

    Answer: A. The method or variable belongs to the class itself.

 

 16. How do you convert a string to an integer in C?

    A. int.Parse(string)

    B. Convert.ToInt32(string)

    C. int.TryParse(string, out int result)

    D. All of the above

    Answer: D. All of the above

 

 17. Which method is used to add an element to a list in C?

    A. list.append()

    B. list.add()

    C. list.insert()

    D. list.Add()

    Answer: D. list.Add()

 

 18. How do you check if two strings are equal in C?

    A. str1 == str2

    B. str1.Equals(str2)

    C. string.Compare(str1, str2)

    D. All of the above

    Answer: D. All of the above

 

 19. Which of the following is not a loop structure in C?

    A. for

    B. foreach

    C. while

    D. repeat

    Answer: D. repeat

 

 20. How do you define a property in C?

    A.     public int MyProperty { get; set; }

    B.     public int MyProperty { get; get; }

    C.     public int MyProperty { set; set; }

    D.     public int MyProperty { set; get; }

    Answer: A.   public int MyProperty { get; set; }

    

  21. Which keyword is used to prevent a class from being inherited?

    A. static

    B. sealed

    C. abstract

    D. final

    Answer: B. sealed

 

 22. How do you declare a delegate in C?

    A. public delegate int MyDelegate();

    B. delegate int MyDelegate();

    C. public delegate int MyDelegate;

    D. delegate int MyDelegate;

    Answer: B. delegate int MyDelegate();

 

 23. What is the purpose of the using statement in C?

    A. To include namespaces.

    B. To handle resources.

    C. To manage memory.

    D. To declare variables.

    Answer: B. To handle resources.

 

 24. Which of the following is not a valid C keyword?

    A. volatile

    B. override

    C. implicit

    D. inherits

    Answer: D. inherits

 

 25. How do you create an anonymous method in C?

    A. delegate { // code }

    B. new delegate { // code }

    C. new delegate { }

    D. delegate (int x) { // code }

    Answer: A. delegate { // code }

 

 26. What is the output of the following code?

   int x = 10;

   x++;

   Console.WriteLine(x);

  

    A. 9

    B. 10

    C. 11

    D. 12

    Answer: C. 11

 

 27. How do you handle multiple exceptions in C?

    A. try...catch...catch

    B. try...catch...finally

    C. try...catch...multiple

    D. try...catch...all

    Answer: A. try...catch...catch

 

 28. What is the purpose of the finally block in C?

    A. To execute code regardless of an exception.

    B. To handle exceptions.

    C. To declare final variables.

    D. To finalize an object.

    Answer: A. To execute code regardless of an exception.

 

 29. Which keyword is used to return a value from a method in C?

    A. exit

    B. return

    C. break

    D. stop

    Answer: B. return

 

 30. How do you create a readonly property in C?

    A.     public int MyProperty { get; }

    B.     public int MyProperty { get; private set; }   

    C.     public int MyProperty { private get; set; }

    D.     public int MyProperty { get; protected set; }

    Answer: A.     public int MyProperty { get; }

    

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

    A. int

    B. bool

    C. char

    D. string

    Answer: D. string

 

 32. How do you declare an enumeration in C?

    A.     enum Colors { Red, Green, Blue }

    B.     enumeration Colors { Red, Green, Blue }   

    C.     enum Colors: int { Red, Green, Blue }

    D.     enumeration Colors: int { Red, Green, Blue }

    Answer: A.     enum Colors { Red, Green, Blue }

    

 33. What is the purpose of the is keyword in C?

    A. To check the type of an object.

    B. To compare two values.

    C. To declare an interface.

    D. To instantiate an object.

    Answer: A. To check the type of an object.

 

 34. How do you implement an interface in C?

    A.     public class MyClass : IMyInterface { }

    B.     public class MyClass implements IMyInterface { }

    C.     public class MyClass inherit IMyInterface { }

    D.     public class MyClass include IMyInterface { }

    Answer: A.     public class MyClass : IMyInterface { }

   

 35. Which of the following is used to define a generic class in C?

    A.     class MyClass<T> { }

    B.     class MyClass<T extends Type> { }

    C.     class MyClass<T implements Type> { }

    D.     class MyClass<T: Type> { }

    Answer: A.     class MyClass<T> { }

    

  36. How do you create a new thread in C?

    A.     Thread t = new Thread(ThreadStart);

    B.     Thread t = create Thread(ThreadStart);

    C.     Thread t = new Thread(Thread);

    D.     Thread t = create Thread(Thread);

    Answer: A.     Thread t = new Thread(ThreadStart);

    

 37. What is the output of the following code?

   int[] arr = {1, 2, 3};

   Console.WriteLine(arr.Length);

    A. 2

    B. 3

    C. 4

    D. 5

    Answer: B. 3

 

 38. Which of the following is not a valid operator in C?

    A. +

    B. -

    C. *

    D. &&

    Answer: D. &&

 

 39. How do you create a lambda expression in C?

    A. (x, y) => x + y

    B. lambda (x, y) { return x + y; }

    C. fun (x, y) => x + y

    D. lambda x, y: x + y

    Answer: A. (x, y) => x + y

 

 40. Which of the following is not a valid data type in C?

    A. int

    B. float

    C. double

    D. real

    Answer: D. real

 

 41. How do you write a multiline comment in C?

    A. / comment /

    B. <! comment >

    C.  comment

    D. // comment //

    Answer: A. / comment /

 

 42. What is the purpose of the ref keyword in C?

    A. To pass a variable by reference.

    B. To pass a variable by value.

    C. To reference a variable.

    D. To refer to an object.

    Answer: A. To pass a variable by reference.

 

 43. Which of the following is not an access modifier in C?

    A. public

    B. protected

    C. internal

    D. friendly

    Answer: D. friendly

 

 44. How do you declare an abstract class in C?

    A.     public abstract class MyClass { }

    B.     public class abstract MyClass { }

    C.     public MyClass abstract { }  

    D.     abstract public class MyClass { }

    Answer: A.     public abstract class MyClass { }

 

 45. What is the output of the following code?

   csharp

   bool isTrue = true;

   Console.WriteLine(isTrue ? "Yes" : "No");

    A. Yes

    B. No

    C. True

    D. False

    Answer: A. Yes

 

 46. How do you implement a method in an interface in C?

    A.     public void MyMethod() { }   

    B.     void MyMethod();    

    C.     void MyMethod { }   

    D.     method void MyMethod { }

    Answer: B.     void MyMethod();

    

 47. What does the this keyword represent in C?

    A. The current instance of the class.

    B. A static reference to the class.

    C. The parent class.

    D. The base class.

    Answer: A. The current instance of the class.

 

 48. How do you declare a nullable type in C?

    A. int?

    B. nullable int

    C. int!

    D. int~

    Answer: A. int?

 

 49. Which of the following is used to compare the values of two strings in C?

    A. ==

    B. Equals()

    C. CompareTo()

    D. All of the above

    Answer: D. All of the above

 

 50. How do you declare a destructor in C?

    A.     ~MyClass() { }    

    B.     destructor MyClass() { }   

    C.     MyClass::~() { }    

    D.     ~MyClass { }   

    Answer: A.     ~MyClass() { }

    

 

 

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