Ruby not giving me an output?

user_18621502 0
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I am using replit because I don't have ruby legitimately set up yet. I'm very new to coding and have minimal knowledge (everything my friend taught me in about 3 hours) and am quite confused. I was typing a code to test something, but when I ran it, it gave me no output.

class Hands 
  attr_reader :name, :element, :skill, :mana, :attack, :fire, :water, :lyfe

  def initialize(name, element, skill)
    @mana = 100
    @name = name
    @element = element
    @skill = skill
  end

  def attack
    if @element = fire
      puts "25"
    elsif @element = water
      puts "15"
    elsif @element = lyfe
      puts "10"
    end
  end
end

player1 = Hands.new('Boyd', 'Fire', 'Craft')

player1.attack

This is my code so far, and from what I know it should work. However when it runs it gives me nothing despite the puts command being in place.

ruby
1 Answers

You've made three common mistakes.

First, using = (assignment) rather than == (test for equality). This works because assigning a value to a variable (in this case an instance variable) returns that value, which is then tested for whether it is true or not, but it does not test if the two things are equal.

if @element = fire
  puts "25"

Is basically the same as writing:

@element = fire
if @element 
  puts "25"

Secondly, you have used attr_reader to create a fire method to read the value in the @fire instaance method, but you have not initialized that @fire variable, so it is nil.

Consequently, all of your if and elsif branches are only triggered is nil is true, but since nil is never true, none of these branches are executed. This is why you see nothing printed.

Thirdly, your conditional expression is not exhaustive. There's no else triggered if none of the other conditions are true. In the event none of the branches of a conditional expression are executed, the conditional expression returns nil, which you can see happen in your case if you run the code in irb.

As a design note, it seems you intend to compare @element to a constant. You more likely want something like the following:

  def attack
    if @element == "fire"
      puts "25"
    elsif @element == "water"
      puts "15"
    elsif @element == "lyfe"
      puts "10"
    end
  end

Or using symbols:

  def attack
    if @element == :fire
      puts "25"
    elsif @element == :water
      puts "15"
    elsif @element == :lyfe
      puts "10"
    end
  end

You could streamline these a bit by using case.

  def attack
    case @element
      when :fire
        puts "25"
      when :water
        puts "15"
      when :lyfe
        puts "10"
    end
  end

But to ensure we can compare @element properly, we should first downcase it and convert to a symbol. This way we don't have to compare to all possible spellings or worry that we're doing a string to symbol comparison that will turn false.

  def attack
    case @element.downcase.to_sym
      when :fire
        puts "25"
      when :water
        puts "15"
      when :lyfe
        puts "10"
    end
  end
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