hats_challenge.rb

# probably the most discussed challenge in the ruby fundamentals
# some nice logic required
 
hat_arr = []
counter = 0 

100.times do
    # here we create the hat array with 100 false items 
    hat_arr[counter] = true
    counter += 1
end 

def toggle(bool)
    # here we create a function that toggles our booleans, if the teacher hits the item the boolean will be toggled whether it's true or false 
    if bool
        return false
    else
        return true
    end
end

def hats(hat_arr)
    # here we pass in the hat array as an argument 
    counter = 0
    while counter <= 100 do
        # here we make sure the teacher will loop through the array of students 100 times
        hat_arr.each_with_index do |bool, index|
            # here we enter into an each loop that inludes the index for each bool (hat) item, if the index modulo by the counter returns zero we know that this is the hat array item that we need to toggle, and we use the toggle function to do this
            # we have to ensure that our index and counter start at 1 for each each pass thus we need to add 1 to the index in the conditional 
            if (index + 1) % (counter + 1) == 0
                hat_arr[index] = toggle(bool)
            end
            # example => so the teacher will toggle every 10 students on the 10th pass, so if student index (student number in line) modulo to the counter (how many gaps between students teacher does for current pass) is equal to zero remainders (10, 20, 30, 40, 50, 60, 70, 80, 90, 100) then the bool value is toggled    
        end
        # this is how we're incremeting the counter value for each loop in the times method
        counter += 1 
    end
    # we return the mutated hat array
    return hat_arr
end

# here we store our mutated hat array after its been through the 100 cycles
hats = hats(hat_arr)

hats.each_with_index do |hat, index|
    # here we print the hat_arr now called hats incrementing the index by 1 
    index + 1
    hat
end

# the index represents the students and the counter represents the gaps between each student 
# by having the counter in the block the while loop doesn't have access to it when it checks the <= condition 
# the block doesn't allow the while loop to have access to the counter variable because the block has its own scope