Count letters in a file C# Exercise - C# Programming Course

// Importing necessary namespaces for file handling
using System;
using System.IO;

public class CharacterCounter
{
    // Method to count occurrences of a character in a file
    public static int CountCharacterInFile(string filePath, char character)
    {
        // Counter to keep track of occurrences of the specified character
        int count = 0;

        // Using StreamReader to read the file
        using (StreamReader reader = new StreamReader(filePath))
        {
            // Looping through each character in the file
            while (!reader.EndOfStream)
            {
                // Reading a character from the file
                char currentChar = (char)reader.Read();

                // Incrementing the counter if the character matches
                if (currentChar == character)
                {
                    count++;
                }
            }
        }

        // Returning the total count of the specified character
        return count;
    }
}

// Auxiliary class with Main method for testing the functionality
public class Program
{
    public static void Main(string[] args)
    {
        // Variables to store the file path and character
        string filePath;
        char character;

        // Checking if both file path and character are provided as arguments
        if (args.Length == 2)
        {
            // Assigning the arguments to variables for clarity
            filePath = args[0];
            character = args[1][0];
        }
        else
        {
            // Prompting the user for the file path if not provided as an argument
            Console.Write("Enter the file path: ");
            filePath = Console.ReadLine();

            // Prompting the user for the character if not provided as an argument
            Console.Write("Enter the character to count: ");
            character = Console.ReadKey().KeyChar;
            Console.WriteLine();
        }

        // Checking if the specified file exists
        if (File.Exists(filePath))
        {
            // Calling the CountCharacterInFile method to get the count of the character
            int count = CharacterCounter.CountCharacterInFile(filePath, character);

            // Displaying the total count to the user
            Console.WriteLine($"The character '{character}' appears {count} times in the file.");
        }
        else
        {
            // Displaying an error message if the file does not exist
            Console.WriteLine("The specified file does not exist.");
        }
    }
}