dictionary_sort.rb

# Your code here to sort the array
def dictionary_sort(array)
  return if array.length <= 1
  array.sort { |word1, word2| word1.downcase <=> word2.downcase }
end

# writing `array.sort` is equivalent to writing `array.sort { |i, j| i <=> j }`
# .sort decides which item should be in the front by doing `<=> on each pair of items
# if the block gives -1, i goes to the front and j goes to the back
# if the block gives 1, j goes to the front and i goes to the back

# eg. ["z", "a", "f"].sort { |i, j| j <=> i }
# first the block will do "z" <=> "a"
# for the pair ["z", "a"] the block returns 1, thus it'll swap position of 'a' and 'z'
# the arr becomes ["a", "z", "f"]
# next the block will do "a" <=> "f" (second pair in the original array)
# for the pair ["a", "f"] the block returns -1, thus it'll not swap the position of 'a' and 'f'
# the arr becomes ["a", "z", "f"]
# finally the block does "z" <=> "f"
# for the pair ["z", "f"] the block returns 1, thus it'll swap 'f' and 'z'
# the arr finally becomes ["a", "f", "z"]

## NOTE: the pairs may come in differently when the array has length more than 3

# if you want to observe the pairs you can do this
# def sort(arr)
# 	arr.sort do |i, j|
# 		puts "i = #{i}"
# 		puts "j = #{j}"
# 		puts
		
# 		i <=> j
# 	end
# end


def puts_with_prompt(str)
  puts str
  print ">> "
end

# ...your code here to initialize the program and take user input
def run
  arr = []
  puts_with_prompt 'Type a word:'
  until (str = gets.chomp) == ''
    arr << str
    puts_with_prompt "Type another word (or press enter to finish):"
  end
 
  result = dictionary_sort(arr)
  puts "Congratulations! Your dictionary has #{arr.length} words:"
  puts result
end

run