C# MCQs with Answers | C Sharp and .NET Questions – Page 2

Question 21 C#

Which C# access modifier limits a member to derived classes that are in the same assembly?

Correct answer C. private protected

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Question 22 C#

Where is a member marked protected internal accessible in C#?

Correct answer D. Anywhere in the same assembly, or in derived classes in any assembly

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Question 23 C#

What is the default accessibility of a member declared inside a C# class with no access modifier?

Correct answer B. private

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Question 24 C#

Since C# 8, what can an interface member include that it could not before?

Correct answer B. A default implementation used when the implementing class does not provide one

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Question 25 C#

What does the sealed modifier do when applied to a C# class?

Correct answer A. It prevents other classes from inheriting from it

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Question 26 C#

Which statement about an abstract class in C# is true?

Correct answer A. It cannot be instantiated directly and may contain abstract members without bodies

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Question 27 C#

Given class A { public string M() => “A”; } class B : A { public new string M() => “B”; }, what does A x = new B(); Console.WriteLine(x.M()); print?

Correct answer B. A

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Question 28 C#

Given class A { public virtual string M() => “A”; } class B : A { public override string M() => “B”; }, what does A x = new B(); Console.WriteLine(x.M()); print?

Correct answer C. B

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Question 29 C#

Which C# keyword calls a constructor of the base class from a derived class constructor?

Correct answer D. base

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Question 30 C#

What does a Predicate delegate return?

Correct answer D. bool

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Question 31 C#

What is the purpose of implementing IDisposable in a C# class?

Correct answer B. To give callers a Dispose method that releases unmanaged or expensive resources deterministically

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Question 32 C#

What happens when you read a missing key with the indexer of a Dictionary in C#?

Correct answer D. A KeyNotFoundException is thrown

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Question 33 C#

In C#, why can an IEnumerable be assigned to a variable of type IEnumerable?

Correct answer A. Because IEnumerable<out T> is covariant in T

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Question 34 C#

What does default(T) produce in a C# generic method?

Correct answer B. null for reference types and the zero value for value types

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Question 35 C#

Which generic constraint requires a type argument in C# to have a public parameterless constructor?

Correct answer C. where T : new()

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Question 36 C#

What does the event keyword add when applied to a delegate field in a C# class?

Correct answer C. Outside code can only subscribe with += and unsubscribe with -=, not invoke or replace it

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Question 37 C#

When a multicast delegate with a return value invokes several methods, what value does the call return?

Correct answer C. The return value of the last method in the invocation list

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Question 38 C#

What is printed by: var acts = new List(); for (int i = 0; i < 3; i++) acts.Add(() => Console.Write(i)); foreach (var a in acts) a();?

Correct answer D. 333

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Question 39 C#

Which built-in delegate type should represent a method that takes a string and returns nothing?

Correct answer B. Action<string>

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Question 40 C#

In the C# delegate type Func, what is bool?

Correct answer B. The return type

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