#Problem
#Write a method that computes the difference between the square of the sum of the first n positive integers and the sum of the squares of the first n positive integers.
#(3) == 22
   # -> (1 + 2 + 3)**2 - (1**2 + 2**2 + 3**2)
   #    (n + n + n)**2 - (n**2 + n**2 + n**2)

#Examples:
#sum_square_difference(3) == 22
   # -> (1 + 2 + 3)**2 - (1**2 + 2**2 + 3**2)
#sum_square_difference(10) == 2640
#sum_square_difference(1) == 0
#sum_square_difference(100) == 25164150

#Data Types:
 #Input: an integer.
 #Output: an integer. sum of squares minus squares of sums
 #Structure: to_s.chars, map method, each, **upto method** or **times method**

#Algorithm/Logic:
 #sq_sum = 0
 #sum_square = 0
 #1.upto(integer) do |num|
 #sq_sum += num ##square sq_num later##
 #sum_squares += num**2
 #retrun sq_sum ** - sum_square

def sum_square_difference(number)
  sq_sum = 0
  sum_of_sq = 0
  1.upto(number) do |num|
    sq_sum += num #**2 on sq_sum later
    sum_of_sq += num**2
  end
  p (sq_sum**2) - sum_of_sq
end

p sum_square_difference(3) == 22
   # -> (1 + 2 + 3)**2 - (1**2 + 2**2 + 3**2)
p sum_square_difference(10) == 2640
p sum_square_difference(1) == 0
p sum_square_difference(100) == 25164150