StreamReader and StreamWriter in C Sharp (C#) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to open a file for reading using StreamReader.

C Sharp (C#)

using System.IO;

var reader = new StreamReader([1]);
string content = reader.ReadToEnd();
reader.Close();

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

AFile.txt

Bfile.txt

C"file.txt"

Dfile

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to put the file name in quotes.

Using incorrect capitalization without quotes.

The file path must be a string literal, so it needs to be in quotes.

2fill in blank

medium

Complete the code to write text to a file using StreamWriter.

C Sharp (C#)

using System.IO;

using (var writer = new StreamWriter([1]))
{
    writer.WriteLine("Hello World");
}

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

Afile

Bfile.txt

CFile.txt

D"file.txt"

Attempts:

3 left

💡 Hint

Common Mistakes

Using the file name without quotes.

Using incorrect capitalization without quotes.

The file path must be a string literal enclosed in double quotes.

3fill in blank

hard

Fix the error in the code to properly read a line from a file.

C Sharp (C#)

using System.IO;

var reader = new StreamReader("data.txt");
string line = reader.[1]();
reader.Close();

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

Areadline

BReadLine

CreadLine

DReadline

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase letters in method names.

Incorrect capitalization causing method not found errors.

The method name is case-sensitive and must be exactly ReadLine with capital R and L.

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> { "apple", "cat", "banana", "dog" };
var lengths = words.Where(w => w.Length > 3).ToDictionary([1], [2]);

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Aw => w

Bw => w.Length

Cw => w.Length > 3

Dw => w.ToUpper()

Attempts:

3 left

💡 Hint

Common Mistakes

Using a condition as a key or value selector.

Using ToUpper() instead of length for values.

The dictionary keys are the words themselves (w => w), and the values are their lengths (w => w.Length).

5fill in blank

hard

Fill all three blanks to create a dictionary with uppercase keys and values for words longer than 4 characters.

C Sharp (C#)

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

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

A3

B4

Cw => w.ToUpper()

Dw => w

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong length filter number.

Swapping keys and values in ToDictionary.

Filter words longer than 4, use uppercase word as key (w => w.ToUpper()), and original word as value (w => w).