loops - simple q on 'while' method in Ruby -

i writing "while" loop method below:

objective: find position of first letter that's vowel in give word "stackoverflow"

vowels = ["a","e","i","o","u",] word = "stackoverflow" n = 0     while vowels.include? word[n] == false     n += 1     end print n 

question: why n return 0? opposed 2 first "o" letter in "stackoverflow

operator precedence in while loop evaluation. try (vowels.include? word[n]) == false evaluate check vowel , compare false.

you face different issue if there no vowel in "word"