C#

Question 1

True or false: You can convert a bool to an int

Answer 1

False

Question 2

Which type of object holds the actual data?

Answer 2

Value

Question 3

Which type of object holds only a reference to the data?

Answer 3

Reference

Question 4

How do you create a nullable value type?

Answer 4

Appending a ? to the

Question 5

What can you do to reduce the amount of code you have to write when using a namespace?

Answer 5

Add the using keyword with the namespace as a top-level statement.

Question 6

Can an abstract class be instantiated?

Answer 6

No

Question 7

What makes a record different from a class is that the equality between objects means…

Answer 7

All of the types, properties and field values match.

Question 8

Equality between two class objects means…

Answer 8

The two objects are the same object.

Question 9

C# does not allow multiple inheritance. What can you use to mimic that behavior?

Answer 9

Interface

Question 10

C# delegates is what and how do they compare to JS callbacks?

Answer 10

It is a type that stores a function pointer. It can be used to create callbacks but is not its only function.

Question 11

Converting from a value type to a reference type is called…and conversion is…

Answer 11

Boxing

Question 12

Converting from a reference type to a value type is called…and conversion is…

Answer 12

Unboxing explicit conversion (cast)

Question 13

The main difference between string and stringbuilder is what? When would you use one over the other?

Answer 13

if a string is changed it creates a new instance whereas stringbuilder modifies the same instance. Use stringbuilder when performance is favored. (Large loops)

Question 14

What is a sealed class?

Answer 14

A class that can not be inherited from.

Question 15

What is a partial class?

Answer 15

A class that is defined into segmented parts within the same file or different files.

Question 16

A constant can never be changed, when can a readonly be changed?

Answer 16

Only in a non-static constructor.

Question 17

When does a ref get initialized? When does an out?

Answer 17

Ref get’s initialized before a method gets called where an out get’s initialized within the method. out for out only

Question 18

Extension methods are a way to add to what?

Answer 18

An existing class library without modifying the original type definition class. Ex. Adding a method to the int class.

Question 19

Early Binding Polymorphism has the overridden methods where? What conditions must be met?

Answer 19

In the same class definition. It is required that the methods have different signatures such as different number of parameters or different order of parameters.

Question 20

Late Binding Polymorphism has the overridden methods where? What conditions must be met?

Answer 20

In the inherited classes. We would declare the method as virtual and override them in any way we want to in the inherited class. The signatures can be identical in this case.

Question 21

What makes an indexer different from a property?

Answer 21

Indexers use the this keyword so that the object can be treated as an array. (From my understanding, creating a property that has an array type adds one word to code so this is kind of dumb)

Question 22

Name the three main access modifiers.

Answer 22

public, private, protected

Question 23

What is the most basic definition of serialization?

Answer 23

Converting an object to a stream of bytes.

Question 24

What is a simple way to describe a jagged array?

Answer 24

An array of arrays.