separate_comma(number).rb

def separate_comma(number)
s = number.to_s
array = []

s.length.times do |i|
	array << s[i].chr
end

array_r =  array.reverse

array_r.length.times do |i|
	unless (i+1) == array_r.length
		if (i+1) % 3 == 0 
			array_r[i] = "," + array_r[i] 
		end
	end
end
array_r.reverse.to_s
end

puts num = rand(rand(100000000000))*rand(rand(1000000000000))
puts separate_comma(num)
puts separate_comma(num).class
puts
puts num1 = rand(999)
puts a = separate_comma(num1)
puts true if /^\d{1,3}$/.match(a)
puts
puts num2 = rand(999999-1000)+1000
puts b = separate_comma(num2)
puts true if /^\d{1,3},\d{3}$/.match(b)
puts
puts num3 = rand(999999999-1000000)+1000000
puts c = separate_comma(num3)
puts true if /^\d{1,3},\d{3},\d{3}$/.match(c)