C# Online Exam

Q1: Which keyword is used to define a class in C#?

A) define
B) struct
C) class
D) object

Q2: What is the default access modifier for class members in C#?

A) public
B) protected
C) internal
D) private

Q3: Which of these is the correct syntax to write a main method in C#?

A) public static void Main()
B) static void main()
C) void Main()
D) Main()

Q4: Which C# keyword is used to inherit a class?

A) inherits
B) extends
C) base
D) :

Q5: Which of the following is used to handle exceptions in C#?

A) try-catch
B) try-except
C) handle
D) catch-except

Q6: Which type represents a true/false value in C#?

A) boolean
B) bool
C) bit
D) flag

Q7: Which keyword is used to define a constant in C#?

A) const
B) define
C) readonly
D) final

Q8: Which of these is NOT a value type in C#?

A) int
B) float
C) decimal
D) string

Q9: Which access modifier allows access within the same assembly?

A) public
B) private
C) internal
D) protected

Q10: Which symbol is used for single-line comments in C#?

A) //
B) #
C) --
D) /* */

Q11: Which keyword is used to declare an abstract class in C#?

A) virtual
B) abstract
C) interface
D) base

Q12: Which method is automatically called when an object is destroyed?

A) dispose()
B) clear()
C) finalize()
D) delete()

Q13: Which class is the base of all classes in C#?

A) System.Object
B) System.Base
C) Object.Base
D) Base.Object

Q14: What is boxing in C#?

A) Converting object to value type
B) Converting value type to object
C) Unwrapping object
D) None

Q15: Which keyword is used to create a new object?

A) object
B) class
C) new
D) create

Q16: Which statement is used to jump out of a loop?

A) continue
B) stop
C) end
D) break

Q17: Which collection stores key-value pairs?

A) Array
B) List
C) Dictionary
D) Set

Q18: What is the output of Console.WriteLine(3 + "3");

A) 6
B) 33
C) 3+3
D) Error

Q19: Which keyword makes a method not overridable?

A) sealed
B) static
C) final
D) override

Q20: What is the output of Console.WriteLine(true && false);

A) true
B) false
C) 1
D) 0

Q21: What is the base type of all exceptions in C#?

A) Exception
B) BaseException
C) Error
D) SystemException

Q22: Which of the following is NOT a loop in C#?

A) for
B) foreach
C) loop
D) while

Q23: What is the size of int in C#?

A) 2 bytes
B) 4 bytes
C) 8 bytes
D) Platform dependent

Q24: What is the extension for C# source files?

A) .cs
B) .c#
C) .c
D) .cs#

Q25: Which of the following allows multiple methods with the same name?

A) Overloading
B) Overriding
C) Shadowing
D) Extending

Q26: What is the purpose of 'using' directive in C#?

A) Import namespaces
B) Free memory
C) Access private members
D) Declare variables

Q27: Which of the following is true about interfaces in C#?

A) Can contain implementation
B) Can’t be inherited
C) Support multiple inheritance
D) Can have private methods

Q28: Which access modifier allows access to derived classes only?

A) private
B) internal
C) protected
D) sealed

Q29: Which type can store null in C#?

A) int
B) bool
C) Nullable
D) float

Q30: Which class is used for console input/output in C#?

A) InputOutput
B) Console
C) Scanner
D) SystemIO

Q31: What is the purpose of 'static' keyword?

A) Create a new object
B) Shared across all instances
C) Defines a class
D) None of the above

Q32: What is LINQ?

A) Library
B) Language extension
C) Query language in C#
D) Loop structure

Q33: What does 'ref' keyword do?

A) Pass by value
B) Pass by reference
C) Read-only reference
D) None

Q34: What is a delegate in C#?

A) Event handler
B) Function pointer
C) Variable
D) Object

Q35: What is the purpose of 'readonly' in C#?

A) Defines a constant
B) Allows runtime constant
C) Prevents method overriding
D) Private method

Q36: Which keyword is used to handle an exception after try?

A) throw
B) except
C) catch
D) handle

Q37: Which keyword throws an exception in C#?

A) error
B) raise
C) throw
D) exception

Q38: Which operator is used to check equality in C#?

A) =
B) ==
C) !=
D) equals()

Q39: What is the return type of Main() method in C#?

A) void
B) int
C) string
D) Main

Q40: Which keyword is used to define an interface?

A) class
B) interface
C) struct
D) type

Q41: What is inheritance in C#?

A) Data hiding
B) Code reuse
C) Data abstraction
D) Encapsulation

Q42: Which symbol is used for multiline comments in C#?

A) //
B) #
C) /* */
D) --

Q43: What is the output type of Console.ReadLine()?

A) char
B) int
C) string
D) object

Q44: Which type is used for large text in C#?

A) String
B) char
C) Text
D) StringBuilder

Q45: Which of the following is NOT a value type?

A) int
B) enum
C) float
D) Array

Q46: Which method is called to clean up unmanaged resources?

A) Dispose()
B) Clear()
C) Delete()
D) Reset()

Q47: Which of the following is a reference type?

A) int
B) char
C) string
D) bool

Q48: Which operator is used for conditional logic in C#?

A) &&
B) ??
C) ?:
D) ==

Q49: Which tool compiles C# code?

A) JVM
B) CLR
C) CSC
D) ILC

Q50: Which keyword is used to define a constant in C#?

A) constant
B) const
C) readonly
D) final