Reference assignment and shared state in C Sharp (C#) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to assign the list to another variable.

C Sharp (C#)

List<int> numbers = new List<int> {1, 2, 3};
List<int> copy = [1];

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

Anull

Bnew List<int>()

Cnumbers

Dcopy

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'new List()' creates a new empty list instead of referencing the existing one.

Assigning 'null' breaks the reference.

Assigning numbers to copy makes both variables refer to the same list.

2fill in blank

medium

Complete the code to add an item to the list through the second reference.

C Sharp (C#)

List<string> fruits = new List<string> {"apple", "banana"};
List<string> basket = fruits;
basket.[1]("orange");

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ARemove

BAdd

CClear

DInsert

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Remove' deletes items instead of adding.

Using 'Clear' empties the list.

Using Add adds a new item to the list referenced by both variables.

3fill in blank

hard

Fix the error in the code to correctly copy the list without shared state.

C Sharp (C#)

List<int> original = new List<int> {1, 2, 3};
List<int> copy = original.[1]();

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AClone

BCopyTo

CClear

DToList

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Clone' is not available for List.

Using 'CopyTo' copies elements to an array, not a new list.

ToList() creates a new list with the same elements, avoiding shared state.

4fill in blank

hard

Fill both blanks to create a dictionary with word lengths for words longer than 3 characters.

C Sharp (C#)

var words = new List<string> {"cat", "house", "tree", "a"};
var lengths = words.Where(w => w.[1] > 3)
    .ToDictionary(w => w, w => w.[2]);

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ALength

BCount

CLength()

DCount()

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Count' or 'Count()' which are for collections, not strings.

Using 'Length()' which is invalid because Length is not a method.

Use the Length property to get the length of a string in C#.

5fill in blank

hard

Fill all three blanks to create a dictionary with uppercase keys and values for words longer than 2 characters.

C Sharp (C#)

var words = new List<string> {"dog", "cat", "bird", "a"};
var result = words.Where(w => w.[1] > 2)
    .ToDictionary(w => w.[2](), w => w.[3]());

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ALength

BToUpper

CToLower

DCount

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Count' instead of 'Length' for string length.

Using 'ToLower()' instead of 'ToUpper()' for uppercase conversion.

Use Length to check string length and ToUpper() to convert strings to uppercase.