Step by Step solution about How to resolve the algorithm Menu step by step in the Ruby programming language

The provided Ruby code defines a method called select that prompts the user to select an item from a list of items and returns the selected item. Here's a breakdown of the code:

1. select Method:

   • The select method takes two parameters:
     • prompt: A string that displays the prompt to the user.
     • items: An optional array of items to choose from. If not provided, it defaults to an empty array.

2. Empty List Handling:

   • If the items array is empty, the method returns an empty string.

3. User Input Loop:

   • If the items array is not empty, the method enters a loop to get user input.
   • Each item in the items array is displayed with its index.
   • The user is prompted to enter an integer corresponding to the index of their choice.
   • The loop continues until the user enters a valid index within the range of the array.

4. Validating User Input:

   • The user's input is converted to an integer using Integer(gets).
   • If the user's input is not a valid integer, it will cause an ArgumentError.
   • In case of an error, the redo keyword is used to restart the loop.

5. Returning Selected Item:

   • Once the user enters a valid index, the method returns the corresponding item from the items array.

6. Testing the Method:

   • Two tests are included to demonstrate the functionality of the select method:
     • The first test provides an empty list and prints the returned empty string.
     • The second test provides a list of four items and prints the user's selected item.

In summary, the select method in Ruby allows you to present a list of items to a user, prompt them to select one, and return the selected item. It includes error handling to ensure valid user input and handles the case of an empty list. The provided tests illustrate how to use the method for both empty and non-empty lists.

def select(prompt, items = [])
  if items.empty?
    ''
  else
    answer = -1
    until (0...items.length).cover?(answer)
      items.each_with_index {|i,j| puts "#{j}. #{i}"}
      print "#{prompt}: "
      begin
        answer = Integer(gets)
      rescue ArgumentError
        redo
      end
    end
    items[answer]
  end
end
 
# test empty list
response = select('Which is empty')
puts "empty list returns: >#{response}<\n"
 
# "real" test
items = ['fee fie', 'huff and puff', 'mirror mirror', 'tick tock']
response = select('Which is from the three pigs', items)
puts "you chose: >#{response}<"