Text replacer C# Exercise - C# Programming Course

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

public class TextReplacer
{
    // Method to replace words in a text file and save the result in a new file
    public static void ReplaceWords(string filePath, string searchWord, string replaceWord)
    {
        // Defining the output file name by appending ".out" to the original file name
        string outputFilePath = filePath + ".out";

        // Using StreamReader to read the input file
        using (StreamReader reader = new StreamReader(filePath))
        // Using StreamWriter to write to the output file
        using (StreamWriter writer = new StreamWriter(outputFilePath))
        {
            // Looping through each line in the input file
            while (!reader.EndOfStream)
            {
                // Reading a line from the input file
                string line = reader.ReadLine();

                // Replacing all occurrences of the search word with the replace word
                string modifiedLine = line.Replace(searchWord, replaceWord);

                // Writing the modified line to the output file
                writer.WriteLine(modifiedLine);
            }
        }

        // Displaying a message indicating where the output has been saved
        Console.WriteLine($"The modified file has been saved as {outputFilePath}");
    }
}

// Auxiliary class with Main method for testing the functionality
public class Program
{
    public static void Main(string[] args)
    {
        // Checking if the correct number of arguments were provided
        if (args.Length != 3)
        {
            // Displaying usage information if the arguments are incorrect
            Console.WriteLine("Usage: replace   ");
            return;
        }

        // Assigning arguments to variables for clarity
        string filePath = args[0];
        string searchWord = args[1];
        string replaceWord = args[2];

        // Checking if the specified file exists
        if (File.Exists(filePath))
        {
            // Calling the ReplaceWords method to perform the replacement
            TextReplacer.ReplaceWords(filePath, searchWord, replaceWord);
        }
        else
        {
            // Displaying an error message if the file does not exist
            Console.WriteLine("The specified file does not exist.");
        }
    }
}