File encrypter C# Exercise - C# Programming Course

// Import the System namespace for basic functionality
using System;  

// Import the IO namespace for file handling
using System.IO;  

// Encrypt class to handle the encryption logic
class Encrypter
{
    // Method to encrypt the content of the input file and save to the output file
    public static void EncryptFile(string inputFilePath, string outputFilePath, string key)
    {
        // Read the content of the input file
        string content = File.ReadAllText(inputFilePath);  

        // Encrypt the content using the key
        string encryptedContent = EncryptContent(content, key);  

        // Write the encrypted content to the output file
        File.WriteAllText(outputFilePath, encryptedContent);  
    }

    // Method to encrypt the content of the file using a simple Caesar cipher
    private static string EncryptContent(string content, string key)
    {
        // Convert the key to a number (for simplicity, just use the length of the key)
        int keyLength = key.Length;  

        // Create a character array to store the encrypted content
        char[] encryptedChars = new char[content.Length];  

        // Loop through each character in the content
        for (int i = 0; i < content.Length; i++)  
        {
            // Get the current character
            char currentChar = content[i];  

            // Encrypt the character using the Caesar cipher (shift by keyLength)
            char encryptedChar = (char)(currentChar + keyLength);  

            // Store the encrypted character
            encryptedChars[i] = encryptedChar;  
        }

        // Convert the encrypted character array back to a string
        return new string(encryptedChars);  
    }
}

class FileEncrypter
{
    static void Main(string[] args)
    {
        // Ask the user for the input file path
        Console.WriteLine("Enter the path of the file to encrypt:");  

        // Get the input file path from the user
        string inputFilePath = Console.ReadLine();  

        // Ask the user for the output file path
        Console.WriteLine("Enter the output file path to save the encrypted file:");  

        // Get the output file path from the user
        string outputFilePath = Console.ReadLine();  

        // Ask the user for the encryption key (simple string-based key)
        Console.WriteLine("Enter the encryption key (any string):");  

        // Get the key from the user
        string key = Console.ReadLine();  

        // Start of try block to handle any file or encryption errors
        try
        {
            // Use the Encrypter class to encrypt the input file and save to the output file
            Encrypter.EncryptFile(inputFilePath, outputFilePath, key);  

            // Inform the user that the encryption process is complete
            Console.WriteLine("File has been successfully encrypted and saved as: " + outputFilePath);  
        }
        catch (Exception ex)  // Catch any exceptions that may occur during the process
        {
            // Print the exception message if an error occurs
            Console.WriteLine("An error occurred: " + ex.Message);  
        }
    }
}