C# for YP

What is the correct way to declare a nullable integer in C#?

• int? number = null;
• int number = null;
• nullable int number = null;
• Int32? number = void;
• None of these

Which of the following is NOT a valid access modifier in C#?

• public
• private
• internal
• package
• None of these

What will be the output of the following code? string str = null;Console.WriteLine(str?.Length ?? 0);

• NullReferenceException
• 0
• null
• Compilation error
• None of these

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

• static
• sealed
• final
• abstract
• None of these

What is the difference between const and readonly in C#?

• No difference, they are synonyms
• const is compile-time constant, readonly is runtime constant
• readonly is compile-time constant, const is runtime constant
• const can be modified, readonly cannot
• None of these

Which collection type is best for frequently adding and removing items from both ends?

• List<T>
• LinkedList<T>
• Queue<T>
• Stack<T>
• None of these

What does the virtual keyword indicate in C#?

• The method cannot be overridden
• The method can be overridden in derived classes
• The method is abstract
• The method is static
• None of these

Which of the following is the correct syntax for exception handling in C#?

• try-catch-finally
• try-except-finally
• begin-rescue-ensure
• attempt-handle-cleanup
• None of these

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

• 11
• 12
• 13
• 10
• None of these

Which interface should a class implement to be used in a foreach loop?

• IEnumerable
• ICollection
• IList
• IComparable
• None of these