Why collections over arrays in C Sharp (C#) - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a list of integers.

C Sharp (C#)

List<int> numbers = new List<int>[1];

Drag options to blanks, or click blank then click option'

A()

B[]

C{}

D<>

Attempts:

3 left

💡 Hint

Common Mistakes

Using square brackets [] instead of parentheses.

Using curly braces {} which are for collection initializers.

In C#, to create a new list, you use parentheses () after the constructor name.

2fill in blank

medium

Complete the code to add an element to the list.

C Sharp (C#)

numbers.[1](5);

Drag options to blanks, or click blank then click option'

AAppend

BAdd

CInsert

DPush

Attempts:

3 left

💡 Hint

Common Mistakes

Using Append which is not a method on List.

Using Push which is used in stacks.

The Add method is used to add an element to a List in C#.

3fill in blank

hard

Fix the error in the code to check if the list contains the number 10.

C Sharp (C#)

bool hasTen = numbers.[1](10);

Drag options to blanks, or click blank then click option'

AHas

BIncludes

CExists

DContains

Attempts:

3 left

💡 Hint

Common Mistakes

Using Has which is not a List method.

Using Includes which is from JavaScript.

The Contains method checks if a list has a specific element.

4fill in blank

hard

Fill both blanks to create a dictionary and add a key-value pair.

C Sharp (C#)

Dictionary<string, int> ages = new Dictionary<string, int>[1];
ages.[2]("Alice", 30);

Drag options to blanks, or click blank then click option'

A()

BAdd

CInsert

D{}

Attempts:

3 left

💡 Hint

Common Mistakes

Using curly braces {} to create the dictionary without initial values.

Using Insert which is not a Dictionary method.

Use parentheses () to create the dictionary and Add to add a key-value pair.

5fill in blank

hard

Fill all three blanks to create a list, add an element, and check its count.

C Sharp (C#)

List<string> fruits = new List<string>[1];
fruits.[2]("Apple");
int count = fruits.[3];

Drag options to blanks, or click blank then click option'

A()

BAdd

CCount

DLength

Attempts:

3 left

💡 Hint

Common Mistakes

Using Length which is for arrays, not lists.

Forgetting parentheses when creating the list.

Create the list with (), add with Add, and get the number of items with Count.