Programming

Question 1

Define : Interface

Answer 1

Defines the things that something makes available to the outside world.

Question 2

Members of an interface are implicitly

Answer 2

public and abstract, and are required to be so.

Question 3

How class indicates that it implements an interface (code example)

Answer 3

public class AwesomeClass : InterfaceName { implementation of methods}

Question 4

You can implement multiple interfaces at the same time

Answer 4

True

Question 5

You can implement interfaces and declare a base class at the same time

Answer 5

True

Question 6

How interface is defined (code example)

Answer 6

public interface InterfaceName { members }

Question 7

A class that implements an interface does not have to provide implementation for all of the members of the class

Answer 7

False

Question 8

A class that implements an interface is allowed to have other members that aren’t defined in the interface

Answer 8

True

Question 9

A class can have more than one base class

Answer 9

False

Question 10

Define : Polymorphism

Answer 10

You can create derived classes that implement the same method in different ways

Question 11

How to implement polymorphism in the base class

Answer 11

mark the method as ‘virtual’

Question 12

How to implement polymorphism in a derived class

Answer 12

mark it ‘override’ and provide alternative implementation

Question 13

How to prevent creation of instance from base class

Answer 13

mark the class as ‘abstract’

Question 14

How to force derived classes to implement methods that don’t exist in base class

Answer 14

In the base class create an empty method marked as abstract

Question 15

New keyword attached to a method means?

Answer 15

A new method is being created unrelated to any methods in the base class. This is not great.

Question 16

What are generics?

Answer 16

A way to create type-safe classes and structs without needing to cmmit to a specific data type at design time.

Question 17

Define a List (code example)

Answer 17

List listofStrings = new List();

Question 18

The core .Net classes that use generics:

Answer 18

List, Dictionary, IEnumerable

Question 19

Define Type-Safety

Answer 19

When you always know what type of object you are working with

Question 20

Using Collection Initializer syntax with a list (code example)

Answer 20

List ListOfInts = new List {1,2,3};

Question 21

Define : IEnumerable

Answer 21

Allows a collection to give others the ability to look at a list one item at a time.

Question 22

Define a Dictionary (code example)

Answer 22

Dictionary phonebook = new Dictionary();

Question 23

Define the problem generics address

Answer 23

Type-safety without creating many similar types

Question 24

Two methods to remove items from a list

Answer 24

RemoveAt and Clear

Question 25

Define a generic class (code example)

Answer 25

public class PracticeList { stuff }

Question 26

What variable structure are generic type names commonly?

Answer 26

Using a single capital letter, generally ‘T’ for singles, or if multiple, like ‘TKey & TValue’

Question 27

What is the default operator?

Answer 27

Used to get default value of a type, for example default(int)

Question 28

Default values for integer, float, bool, char, enum, strings & arrays, struct

Answer 28

integer & float : 0
bool : false
char : 0 / null control character
enum : 0
strings & arrays : null
struct : each element takes default value for its type

Question 29

Generic classes can only have one generic type parameter

Answer 29

false

Question 30

Generic type constraints limit what can be used for the generic type

Answer 30

true

Question 31

Constraints let you use the methods of the thing you are constraining to

Answer 31

True