C# MCQs with Answers | C Sharp and .NET Questions – Page 3

Question 41 C#

What is a delegate in C#?

Correct answer D. A type-safe reference to a method with a specific signature

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Question 42 C#

What does the C# using statement guarantee for an object such as a StreamReader?

Correct answer A. Its Dispose method is called when the block is exited, even if an exception is thrown

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Question 43 C#

What is a local function in C#?

Correct answer C. A method declared inside another method and visible only within it

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Question 44 C#

When does a static constructor run in C#?

Correct answer B. Once, automatically, before the first instance is created or any static member is accessed

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Question 45 C#

What does the with expression do on a C# record, as in var p2 = p1 with { Y = 5 };?

Correct answer B. Creates a copy of p1 with Y changed to 5, leaving p1 unchanged

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Question 46 C#

Given record Point(int X, int Y);, what does Console.WriteLine(new Point(1, 2) == new Point(1, 2)); print?

Correct answer A. True

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Question 47 C#

Given struct P { public int X; }, what does this print: P a = new P { X = 1 }; P b = a; b.X = 5; Console.WriteLine(a.X);?

Correct answer D. 1

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Question 48 C#

What is a key difference between a class and a struct in C#?

Correct answer A. A class is a reference type, while a struct is a value type copied on assignment

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Question 49 C#

Which requirement applies to declaring an extension method in C#?

Correct answer A. It must be a static method in a non-generic static class, with this before the first parameter

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Question 50 C#

What is the output of: string s = null; Console.WriteLine(s?.Length ?? -1);?

Correct answer C. -1

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Question 51 C#

What does the as operator return in C# when the conversion fails?

Correct answer A. null

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Question 52 C#

What is printed by: object o = “hi”; Console.WriteLine(o is string s ? s.Length : -1);?

Correct answer A. 2

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Question 53 C#

What is the output of: int m = int.MaxValue; m++; Console.WriteLine(m); (default project settings)?

Correct answer B. -2147483648

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Question 54 C#

What happens when C# evaluates checked(x + 1) where x is an int variable holding int.MaxValue?

Correct answer B. An OverflowException is thrown

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Question 55 C#

What is the output of: byte b = 255; b++; Console.WriteLine(b);?

Correct answer A. 0

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Question 56 C#

What is the value of r after: int n = 3; string r = n switch { 1 => “one”, 3 => “three”, _ => “other” };?

Correct answer A. three

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Question 57 C#

Which statement about the C# switch statement is true?

Correct answer D. Control cannot fall through from one non-empty case section to the next

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Question 58 C#

Which C# pattern matches a value that is an int greater than 100, as in x is > 100?

Correct answer B. A relational pattern

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Question 59 C#

What does the property pattern s is { Length: > 3 } test in C#?

Correct answer B. That s is not null and its Length property is greater than 3

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Question 60 C#

What happens if you call list.Remove(item) on a List inside a foreach loop over that same list?

Correct answer C. An InvalidOperationException is thrown when the loop continues

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