File paths and Directory operations in C Sharp (C#) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to get the file name from the full path.

C Sharp (C#)

string filePath = @"C:\Users\Public\Documents\report.pdf";
string fileName = System.IO.Path.[1](filePath);
Console.WriteLine(fileName);

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

AGetDirectoryName

BGetFileName

CCombine

DGetExtension

Attempts:

3 left

💡 Hint

Common Mistakes

Using GetDirectoryName returns the folder path, not the file name.

Using GetExtension returns only the file extension.

The GetFileName method extracts the file name from a full file path.

2fill in blank

medium

Complete the code to check if a directory exists at the given path.

C Sharp (C#)

string dirPath = @"C:\Temp\Logs";
bool exists = System.IO.Directory.[1](dirPath);
Console.WriteLine(exists);

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ACreateDirectory

BGetFiles

CExists

DDelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using CreateDirectory will create the directory instead of checking.

Using GetFiles returns files inside the directory, not existence.

The Exists method checks if the directory exists and returns true or false.

3fill in blank

hard

Fix the error in the code to combine two parts of a file path correctly.

C Sharp (C#)

string folder = @"C:\Users\Public";
string file = "data.txt";
string fullPath = System.IO.Path.[1](folder, file);
Console.WriteLine(fullPath);

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AConcat

BJoin

CAppend

DCombine

Attempts:

3 left

💡 Hint

Common Mistakes

Using Join or Concat does not handle path separators correctly.

Append is not a method of Path.

The Combine method correctly joins folder and file names into a valid path.

4fill in blank

hard

Fill both blanks to create a dictionary with file names as keys and their extensions as values from a list of file paths.

C Sharp (C#)

var files = new List<string> { @"C:\Docs\file1.txt", @"D:\Music\song.mp3" };
var fileDict = files.ToDictionary(f => System.IO.Path.[1](f), f => System.IO.Path.[2](f));

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AGetFileName

BGetExtension

CGetDirectoryName

DCombine

Attempts:

3 left

💡 Hint

Common Mistakes

Using GetDirectoryName instead of GetFileName for keys.

Using Combine instead of GetExtension for values.

GetFileName extracts the file name for the dictionary key, and GetExtension extracts the file extension for the value.

5fill in blank

hard

Fill the blanks to create a dictionary with uppercase directory names as keys and the count of files inside as values.

C Sharp (C#)

var dirs = new List<string> { @"C:\Temp", @"D:\Data" };
var dirInfo = dirs.ToDictionary(d => System.IO.Path.[1](d).ToUpper(), d => System.IO.Directory.[2](d).Length);

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AGetDirectoryName

BGetFiles

CGetDirectories

DGetFileName

Attempts:

3 left

💡 Hint

Common Mistakes

Using GetDirectoryName instead of GetFileName for folder name.

Using GetDirectories instead of GetFiles for counting files.

GetFileName gets the last folder name to uppercase for the key, GetFiles returns files to count for the value.

Practice

1. Which C# class is used to check if a directory exists on your computer?

easy

A. Path

B. File

C. Directory

D. StreamReader

Solution

1. Step 1: Understand the purpose of Directory class

   The Directory class provides methods to work with folders, including checking if they exist.

2. Step 2: Identify the correct method for existence check

   Directory.Exists(path) returns true if the folder exists, which is what we need.

3. Final Answer:

   Directory -> Option C

4. Quick Check:

   Directory = Folder check [OK]

Hint: Use Directory class to manage folders easily [OK]

Common Mistakes:

• Confusing File class with Directory for folders
• Using Path class to check existence
• Trying to read folder like a file

2. Which of the following is the correct syntax to create a new directory named "Data" in C#?

easy

A. Directory.Create("Data");

B. File.CreateDirectory("Data");

C. Path.CreateDirectory("Data");

D. Directory.CreateDirectory("Data");

Solution

1. Step 1: Identify the correct method to create directories

   The Directory class has a method called CreateDirectory to make new folders.

2. Step 2: Check method names and classes

   Only Directory.CreateDirectory("Data") is valid syntax; others are incorrect or belong to wrong classes.

3. Final Answer:

   Directory.CreateDirectory("Data"); -> Option D

4. Quick Check:

   CreateDirectory method creates folders [OK]

Hint: Use Directory.CreateDirectory to make folders [OK]

Common Mistakes:

• Using Directory.Create instead of CreateDirectory
• Trying to create directory with File class
• Using Path class for folder creation

3. What will be the output of this C# code?

string folder = "C:\\Users\\Public";
string fileName = "report.txt";
string fullPath = Path.Combine(folder, fileName);
Console.WriteLine(fullPath);

medium

A. C:/Users/Public/report.txt

B. C:\Users\Public\report.txt

C. C:\Users\Publicreport.txt

D. C:\Users\Public\

Solution

1. Step 1: Understand Path.Combine behavior

   Path.Combine joins folder and file name with the correct directory separator for Windows (\).

2. Step 2: Check the combined string output

   The result is "C:\Users\Public\report.txt" with backslashes and a single separator between folder and file.

3. Final Answer:

   C:\Users\Public\report.txt -> Option B

4. Quick Check:

   Path.Combine joins paths with \ [OK]

Hint: Path.Combine joins paths with correct separators [OK]

Common Mistakes:

• Expecting forward slashes instead of backslashes
• Missing separator between folder and file
• Confusing output with folder path only

4. Identify the error in this code snippet that tries to delete a directory:

string path = "C:\\Temp";
if (Directory.Exists(path))
{
    Directory.Delete(path);
    Console.WriteLine("Deleted");
}

medium

A. Directory.Delete requires a second argument to delete non-empty folders

B. Directory.Exists should be File.Exists

C. The path string is incorrectly escaped

D. Console.WriteLine cannot be used inside if

Solution

1. Step 1: Understand Directory.Delete behavior

   Directory.Delete(path) without a second argument only deletes empty folders.

2. Step 2: Check if folder might be non-empty

   If folder has files, Directory.Delete(path, true) is needed to delete recursively.

3. Final Answer:

   Directory.Delete requires a second argument to delete non-empty folders -> Option A

4. Quick Check:

   Delete non-empty folder needs recursive flag [OK]

Hint: Use Directory.Delete(path, true) for non-empty folders [OK]

Common Mistakes:

• Assuming Directory.Delete deletes non-empty folders by default
• Using File.Exists to check folders
• Incorrectly escaping path strings

5. You want to list all subdirectories inside "C:\\Projects" and print their full paths. Which code snippet correctly does this?

hard

A. foreach (var dir in Directory.GetDirectories("C:\\Projects")) { Console.WriteLine(dir); }

B. foreach (var file in Directory.GetFiles("C:\\Projects")) { Console.WriteLine(file); }

C. foreach (var dir in Path.GetDirectories("C:\\Projects")) { Console.WriteLine(dir); }

D. foreach (var dir in Directory.ListDirectories("C:\\Projects")) { Console.WriteLine(dir); }

Solution

1. Step 1: Identify method to get subdirectories

   Directory.GetDirectories(path) returns an array of folder paths inside the given directory.

2. Step 2: Use foreach to print each directory path

   Looping over the array and printing each path is done with foreach and Console.WriteLine.

3. Final Answer:

   foreach (var dir in Directory.GetDirectories("C:\\Projects")) { Console.WriteLine(dir); } -> Option A

4. Quick Check:

   GetDirectories lists folders [OK]

Hint: Use Directory.GetDirectories to list folders [OK]

Common Mistakes:

• Using GetFiles instead of GetDirectories
• Trying to use Path class for directory listing
• Using non-existent Directory.ListDirectories method