NoMethodError using gets.chomp in Ruby

Question

Can anyone help me with this simple exercise?

class Item
  def percents()
    self * 100
  end
end

answer = gets.chomp
puts answer.percents()

The result is:

percents.rb:7:in `<main>': undefined method `percents' for "300":String (NoMethodError)

Answer 1

The variable answer needs to be an Item object in order to have the percents method. Or, you can remove the percents method from the Item class, and have it take in an integer:

def percents(int)
   int * 100
end

answer = gets.chomp
puts percents(answer)

This last line, however, won't do you as you would expect. Since gets.chomp returns a string of your input, you'll be multiplying the string "300" by 100, which means your output will look like this:

2.2.2 :026 > puts percents(answer)
300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300300
 => nil

You can first convert your answer to an int, using to_i, and then print the percent

2.2.2 :027 > puts percents(answer.to_i)
30000
 => nil

There, that looks better. Now if you'd like make your answer an object of class Item, that's a bit more tricky.

class Item
  def initialize(answer)
    @answer = answer
  end

  def percents
    @answer * 100
  end
end

item = Item.new(gets.chomp.to_i)
puts item.percents

Your output will look the same as above:

2.2.2 :049 > puts item.percents
30000
 => nil

Let me know if you have further questions, as I'm not 100% sure of the intent of the program you're trying to write. I'd recommend checking out a few Ruby tutorials like Ruby in Twenty Minutes or Tutorial Point's ruby tutorial in your quest to learn Ruby. I hope this helps!