File paths and Directory operations in C Sharp (C#) - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this directory creation code?

Consider the following C# code that creates a directory and checks if it exists. What will be printed?

C Sharp (C#)

using System;
using System.IO;

class Program {
    static void Main() {
        string path = "TestDir";
        Directory.CreateDirectory(path);
        Console.WriteLine(Directory.Exists(path));
    }
}

A True

B False

C Throws IOException

D Throws UnauthorizedAccessException

💡 Hint

Think about what Directory.CreateDirectory does if the directory already exists.

Directory.CreateDirectory creates the directory if it doesn't exist, or does nothing if it already exists. Directory.Exists returns true if the directory exists, so the output is True.

❓ Predict Output

intermediate

What does this code print about file paths?

Given this C# code snippet, what will be the output?

C Sharp (C#)

using System;
using System.IO;

class Program {
    static void Main() {
        string filePath = "C:\\Users\\Public\\Documents\\report.txt";
        Console.WriteLine(Path.GetFileName(filePath));
    }
}

A report.txt

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

C report

D Documents

💡 Hint

Path.GetFileName returns the file name and extension from a full path.

Path.GetFileName extracts the file name with extension from the full path, so it returns 'report.txt'.

❓ Predict Output

advanced

What is the output of this code listing files?

This code lists files in a directory. What will it print?

C Sharp (C#)

using System;
using System.IO;

class Program {
    static void Main() {
        string dir = "TestDir";
        Directory.CreateDirectory(dir);
        File.WriteAllText(Path.Combine(dir, "file1.txt"), "Hello");
        File.WriteAllText(Path.Combine(dir, "file2.txt"), "World");
        var files = Directory.GetFiles(dir);
        Console.WriteLine(files.Length);
    }
}

A 1

B 2

C Throws DirectoryNotFoundException

D 0

💡 Hint

Files are created before listing, so count should reflect that.

Two files are created in the directory before calling GetFiles, so the length of the files array is 2.

❓ Predict Output

advanced

What error does this code raise when deleting a non-empty directory?

What happens when you run this code that tries to delete a directory containing files?

C Sharp (C#)

using System;
using System.IO;

class Program {
    static void Main() {
        string dir = "TestDir";
        Directory.CreateDirectory(dir);
        File.WriteAllText(Path.Combine(dir, "file.txt"), "data");
        Directory.Delete(dir);
        Console.WriteLine("Deleted");
    }
}

A Throws UnauthorizedAccessException

B Prints 'Deleted'

C Throws IOException

D Throws DirectoryNotFoundException

💡 Hint

Deleting a directory with files without recursive flag causes an error.

Directory.Delete without recursive flag throws IOException if the directory is not empty.

🧠 Conceptual

expert

How many items are in the resulting dictionary after this path manipulation?

Consider this C# code that uses DirectoryInfo and FileInfo objects. How many entries will the dictionary contain?

C Sharp (C#)

using System;
using System.Collections.Generic;
using System.IO;

class Program {
    static void Main() {
        string dir = "TestDir";
        Directory.CreateDirectory(dir);
        File.WriteAllText(Path.Combine(dir, "a.txt"), "A");
        File.WriteAllText(Path.Combine(dir, "b.txt"), "B");
        var dict = new Dictionary<string, long>();
        var directoryInfo = new DirectoryInfo(dir);
        foreach (var file in directoryInfo.GetFiles()) {
            dict[file.Name] = file.Length;
        }
        Console.WriteLine(dict.Count);
    }
}

A Throws IOException

B 0

C 1

D 2

💡 Hint

Each file in the directory is added as a dictionary entry.

Two files are created and added to the dictionary, so the count is 2.