What is the primary purpose of encapsulation in OOP?

The correct answer is B: To hide internal implementation details and control access to data. Encapsulation bundles data and methods together, hiding internal implementation and controlling access through public interfaces, improving maintainability and security.

Which collection type is best suited for implementing a priority queue in C#?

The correct answer is B: PriorityQueue. PriorityQueue was introduced in .NET 6 specifically for priority queue implementation.

Which statement about abstract classes in C# is INCORRECT?

The correct answer is D: Abstract classes cannot have any properties. Abstract classes can have properties, fields, concrete methods, and abstract members. The statement that they cannot have properties is incorrect.

Consider the following code. What will be the output? interface I1 { void Show(); } interface I2 { void Show(); } class C : I1, I2 { public void Show() { Console.WriteLine("C"); } } C obj = new C(); obj.Show();

The correct answer is A: C. A single method implementation satisfies both interface contracts. The method is called and prints 'C'.

A developer needs to create a RESTful API that returns JSON data. Which ASP.NET approach is most suitable?

The correct answer is A: ASP.NET Core Web API with [ApiController]. ASP.NET Core Web API with [ApiController] attribute is the modern approach for building RESTful APIs that return JSON.

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C# Programming

C# and .NET for campus placement

154 Q 4 Topics Take Mock Test

Difficulty: All Easy Medium Hard 121–130 of 154

Topics in C# Programming

All Basics & Syntax 100 OOP in C# 100 Collections 71 ASP.NET Basics 19

Q.121 Medium Basics & Syntax

Which statement about anonymous functions in C# is TRUE?

A Anonymous functions must have a return type

B Lambda expressions are a type of anonymous function

C Anonymous functions cannot access outer scope variables

D All anonymous functions require explicit parameter types

Correct Answer: B. Lambda expressions are a type of anonymous function

EXPLANATION

Lambda expressions (introduced in C# 3.0) are a concise form of anonymous functions. They can infer return types and parameter types, and can access outer scope variables.

Test

Q.122 Medium Basics & Syntax

What is the correct way to create a generic method in C#?

A public void Method() { }

B public void Method() { }

C public void Method[T]() { }

D public T void Method() { }

Correct Answer: A. public void Method() { }

EXPLANATION

Generic methods use angle brackets <T> after the method name. The syntax is: public void Method<T>() where T is the type parameter.

Test

Q.123 Medium Basics & Syntax

In C#, what is the difference between '==' and 'Equals()' when comparing strings?

A No difference, they are identical

B '==' compares references, Equals() compares values for strings

C 'Equals()' is slower than '=='

D '==' can compare null values safely

Correct Answer: B. '==' compares references, Equals() compares values for strings

EXPLANATION

For strings in C#, '==' is overloaded to compare values, and Equals() also compares values. However, for other reference types, '==' compares references while Equals() compares values.

Test

Q.124 Medium Basics & Syntax

Which collection type in C# automatically prevents duplicate values?

A List

B HashSet

C Queue

D Stack

Correct Answer: B. HashSet

EXPLANATION

HashSet<T> is an unordered collection that automatically prevents duplicate values. List<T> allows duplicates.

Test

Q.125 Medium Basics & Syntax

What is the output of: bool result = (5 > 3) && (10 < 8); Console.WriteLine(result);

A true

B false

C null

D error

Correct Answer: B. false

EXPLANATION

5 > 3 is true, but 10 < 8 is false. The && (AND) operator returns false because one condition is false.

Test

Q.126 Medium Basics & Syntax

Which of the following correctly demonstrates the use of an out parameter in C#?

A void Calculate(out int result) { result = 10; }

B void Calculate(in int result) { result = 10; }

C void Calculate(ref int result) { result = 10; }

D void Calculate(int result) { result = 10; }

Correct Answer: A. void Calculate(out int result) { result = 10; }

EXPLANATION

The 'out' keyword is used when a method needs to return a value through a parameter. The parameter must be assigned before the method exits.

Test

Q.127 Medium Basics & Syntax

What will be the output of the following code? int x = 5; int y = ++x; Console.WriteLine(x + " " + y);

A 5 5

B 6 6

C 5 6

D 6 5

Correct Answer: B. 6 6

EXPLANATION

++x is pre-increment, so x becomes 6, then y is assigned 6. Both x and y are 6.

Test

Q.128 Medium Basics & Syntax

Which of the following demonstrates proper use of string interpolation in C# 6.0+?

A $"Name is {name}"

B "Name is " + name

C string.Format("Name is {0}", name)

D "Name is \{name}"

Correct Answer: A. $"Name is {name}"

EXPLANATION

String interpolation uses the $ prefix followed by curly braces containing expressions.

Test

Q.129 Medium Basics & Syntax

What happens when you try to access an array element beyond its length in C#?

A Returns null

B Returns default value of the type

C Throws IndexOutOfRangeException

D Returns the last element

Correct Answer: C. Throws IndexOutOfRangeException

EXPLANATION

Accessing an array index beyond its bounds throws an IndexOutOfRangeException at runtime.

Test

Q.130 Medium Basics & Syntax

Which of the following statements about properties in C# is TRUE?

A Properties can only have get accessors

B Properties can have get and/or set accessors with different access levels

C Properties cannot be overridden

D Properties must have both get and set accessors

Correct Answer: B. Properties can have get and/or set accessors with different access levels

EXPLANATION

Properties can have get and set accessors independently with different access modifiers like public get, private set.

Test

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