**Course Title:** Ruby Programming: From Basics to Advanced Techniques **Section Title:** File Handling and Exception Management **Topic:** Develop a Ruby application that reads from and writes to files with error handling.(Lab topic) **Objective:** By the end of this lab, you will be able to develop a Ruby application that reads from and writes to files with error handling, using the knowledge and skills you've acquired in the previous topics. **Prerequisites:** Before starting this lab, make sure you have completed the following topics: - File Handling and Exception Management - Data Structures - Object-Oriented Programming (OOP) in Ruby - Control Structures and Functions **Lab Requirements:** To complete this lab, you will need: - Ruby installed on your system (RubyInstaller, RVM, or rbenv) - A text editor or IDE (Integrated Development Environment) of your choice - A file named `data.txt` containing the following text: ``` John,Doe,30 Jane,Doe,28 Bob,Smith,35 Alice,Johnson,22 ``` **Step 1: Create a new Ruby file** Create a new file named `file_reader.rb` in your desired directory and add the following code: ```ruby # file_reader.rb # Require the necessary modules require 'csv' # Define a class named FileReader class FileReader def read_file(file_name) # Initialize an empty array to store the data data = [] # Begin the file reading block begin # Open the file in read-only mode File.open(file_name, 'r') do |file| # Read the file line by line file.each_line do |line| # Split the line by comma and store it in an array row = line.chomp.split(',') # Add the row to the data array data << row end end rescue StandardError => e # Handle any exceptions puts "Error reading file: #{e.message}" end # Return the data array data end end ``` **Step 2: Create a FileWriter class** In the same file, add the following code: ```ruby # file_reader.rb # Define a class named FileWriter class FileWriter def write_file(file_name, data) # Begin the file writing block begin # Open the file in write-only mode File.open(file_name, 'w') do |file| # Write each data row to the file data.each do |row| file.puts row.join(',') end end rescue StandardError => e # Handle any exceptions puts "Error writing file: #{e.message}" end end end ``` **Step 3: Test the FileReader and FileWriter classes** Add the following code to test the classes: ```ruby # file_reader.rb # Create instances of FileReader and FileWriter file_reader = FileReader.new file_writer = FileWriter.new # Read data from the file data = file_reader.read_file('data.txt') # Print the read data puts "Read data:" data.each do |row| puts row end # Modify the data data[0][0] = 'Jim' # Write the modified data to a new file file_writer.write_file('new_data.txt', data) # Read the new data new_data = file_reader.read_file('new_data.txt') # Print the new data puts "New data:" new_data.each do |row| puts row end ``` **Run the code** Run the code using the command `ruby file_reader.rb` in your terminal. **Output:** The output should be: ``` Read data: ["John", "Doe", "30"] ["Jane", "Doe", "28"] ["Bob", "Smith", "35"] ["Alice", "Johnson", "22"] New data: ["Jim", "Doe", "30"] ["Jane", "Doe", "28"] ["Bob", "Smith", "35"] ["Alice", "Johnson", "22"] ``` **Conclusion:** In this lab, you developed a Ruby application that reads from and writes to files with error handling using the `FileReader` and `FileWriter` classes. You also learned how to modify the data and write it to a new file. **Practice Exercise:** 1. Modify the `FileReader` class to read data from a CSV file instead of a text file. 2. Add a method to the `FileWriter` class to append data to an existing file. 3. Use the `FileUtils` module to copy a file from one location to another. **Leave a comment or ask for help:** If you have any questions or need help with the lab, please leave a comment below. I'd be happy to assist you. **References:** 1. Ruby Documentation: [File](https://ruby-doc.org/core-2.6.3/File.html) 2. Ruby Documentation: [FileUtils](https://ruby-doc.org/stdlib-2.6.3/libdoc/fileutils/rdoc/FileUtils.html) 3. CSV Library: [csv](https://github.com/ruby/csv) **What's next?** In the next topic, we'll cover [Understanding modules and their uses](https://github.com/ruby/ruby/blob/master/doc/modules.rdoc). Get ready to learn about the fundamentals of modular programming in Ruby!