title: Function to count vowels in a string
body: <p>Why isnt this working?</p>
  
  <pre><code>def count_vowels(string)
    result = 0
    i = 0
    while i &lt; string.length
      if string[i] == "a" ||"e" || "i" || "o" || "u"
        result = result + 1
        i += 1
      end
      return result
    end
  </code></pre>