Fibonacci number on a range (ruby)

Question

Could someone give me a brief explanation as to why n+(n-1) doesn't work? Mathematically it does but i'm not sure how to tell ruby this is what i'm looking for? As the title suggests, the code is supposed to return a Fibonacci sequence.

startyear = []
(1..100).each do |n|
  puts n+(n-1)
  startyear.push(n)
end

Possible duplicate of [Fibonacci sequence in Ruby (recursion)](http://stackoverflow.com/questions/12178642/fibonacci-sequence-in-ruby-recursion) — James Black, Mar 24 '16 at 02:28

score 2 · Accepted Answer · answered Mar 24 '16 at 02:47

2

n+(n-1) = 2n-1. Your code is simply displaying 2n-1 (1,3,5,7,..,199).

On the other hand, startyear.push(n) is pushing numbers (1,2,3,.,100) into the startyear array. I think you meant to do something like this.

startyear = [1,1]
(2..100).each do |n|
  puts (new_num = startyear[n-1] + startyear[n-2])
  startyear.push(new_num)
end

But again, I'm not 100% sure what the range stands for in your code, so I might be wrong.

answered Mar 24 '16 at 02:47

cozyconemotel

1,121
2
10
22

the range is meant to break to code when the value reaches => 100 – whatabout11 Mar 24 '16 at 02:50
1

I think this answers my question, I added a break into the code. Thank you! – whatabout11 Mar 24 '16 at 02:57

Fibonacci number on a range (ruby)

1 Answers1