Vowel

# Let's go back to the exercise where we determined what is and isn't a vowel.
# With ruby, there's always more than one way to do something and get the same
# result.

# Assuming vowels `a,e,i,o,u`:

# 1. Write a method that returns whether a given letter is a vowel, using `if`
# and `elsif` 

def is_vowel_one?(letter)
  letter.downcase!
  if letter == "a" 
    true
  elsif letter == "e"
    true
  elsif letter == "i"
    true
  elsif letter == "o"
    true
  elsif letter == "u"
    true
  else
    false
  end
end

# 2. Write a method that returns whether a given letter is a vowel,
# using `case` 

def is_vowel_two?(letter)  
  letter.downcase!
  
  case letter
  when "a"
    true
  when "e"
    true
  when "i"
    true
  when "o"
    true
  when "u"
    true
  else
    false
  end
end

# 3. Write a method that returns whether a given letter is a vowel,
# using `if` with no `else`, all on a single line 

def is_vowel_three?(letter)
  ["a","e","i","o","u"].each { |vowel| return true if vowel == letter }
  false
end

# 4. Write a method that returns
# whether a given letter is a vowel without using `if` or `case` while all on a
# single line 

def is_vowel_three?(letter)
  ["a","e","i","o","u"].include?(letter.downcase)
end

# 5. Write a method that returns whether a given letter is a vowel
# without checking equality, or the use of `if`, using the array of vowels 

def is_vowel_four?(letter)
   ["a","e","i","o","u"].include?(letter.downcase)
end

# 6. Write a method that will evaluate a string and return the first vowel found in
# the string, if any 
def first_vowel(word)
  letter_array = word.each_char.to_a
  for i in 0..(word.length - 1) do
    return letter_array[i] if ["a","e","i","o","u"].include?(letter_array[i].downcase)
  end
end

# 7. Write a method that will evaluate a string and return
# the ordinal position (index) of the string where the first vowel is found, if
# any

def first_vowel_two(word)
  letter_array = word.each_char.to_a
  for i in 0..(word.length - 1) do
    return [i] if ["a","e","i","o","u"].include?(letter_array[i].downcase)
  end
  "No vowel found"
end


# *hint: remember that every line of ruby code has a return value, and that a
# *method will return the result of the last operation