HashSet for unique elements in C Sharp (C#) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a HashSet of integers.

C Sharp (C#)

HashSet<int> numbers = new [1]<int>();

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AHashSet

BList

CDictionary

DQueue

Attempts:

3 left

💡 Hint

Common Mistakes

Using List instead of HashSet, which allows duplicates.

Using Dictionary which requires key-value pairs.

The HashSet class is used to store unique elements. Here, we create a new HashSet of integers.

2fill in blank

medium

Complete the code to add an element to the HashSet.

C Sharp (C#)

numbers.[1](5);

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APush

BAppend

CAdd

DInsert

Attempts:

3 left

💡 Hint

Common Mistakes

Using Insert which is not a method of HashSet.

Using Push or Append which are not valid methods here.

The Add method adds an element to the HashSet if it is not already present.

3fill in blank

hard

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

C Sharp (C#)

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

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AContains

BExists

CIncludes

DHas

Attempts:

3 left

💡 Hint

Common Mistakes

Using Has or Includes which are not valid in C# HashSet.

Using Exists which is a LINQ method, not a HashSet method.

The Contains method checks if an element exists in the HashSet.

4fill in blank

hard

Fill both blanks to create a HashSet from an array and check if it contains 3.

C Sharp (C#)

int[] arr = {1, 2, 3, 4};
HashSet<int> set = new [1](arr);
bool hasThree = set.[2](3);

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AHashSet

BContains

CList

DAdd

Attempts:

3 left

💡 Hint

Common Mistakes

Using List instead of HashSet for unique elements.

Using Add instead of Contains to check membership.

We create a HashSet from the array arr. Then we use Contains to check if 3 is in the set.

5fill in blank

hard

Fill all three blanks to add elements and check the count of unique items.

C Sharp (C#)

HashSet<string> fruits = new [1]();
fruits.[2]("apple");
fruits.[3]("banana");
int count = fruits.Count;

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

AHashSet

BAdd

DInsert

Attempts:

3 left

💡 Hint

Common Mistakes

Using Insert which is not a method of HashSet.

Confusing Add with other collection methods.

We create a HashSet of strings, add "apple" and "banana" using Add, then get the count of unique items.