CODEWITHSUNDEEP
ruby
Alek
Alek

Reputation: 1481

Trying to make factorial function

I am trying to make factorial calculation here.

When I run this code, it returns me number 5. I suppose this code loops only once, so only number 5(attr) is added to array. Am I right, and what should I do?

And I don't want solution, I want advice :)

def factorial attr
  array = []

  attr.downto(1) do |x|
    array << x
    array.reduce(:*)
  end
end

p factorial(5)

Upvotes: 0

Views: 34

Answers (1)

Nick Veys
Nick Veys

Reputation: 23939

Ruby returns the value of the last expression in the method as the value, and that's the .downto block. Your code definitely loops, but it reduces "5" times, and discards the value! So you're getting this, essentially:

(502)⚡️ irb
2.2.0 :001 > 25.downto(1) { |x| }
 => 25

Try moving your reduce statement outside of the block (below), so the downto stuffs the values into the array, then you reduce it using the * operation.

Upvotes: 1

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