def generate_array(size)
  array = []
  size.to_i.times { array << rand(-10..20) }
  array
end
#have some questions accroding to this task (probably, it can be done with 'each'?!)
def insert_zeros_to_array(array)
  i = 0
  while(i < array.size) do
    if array[i] > 0
      array.insert(i, 0)
      i += 2
    end
    i += 1
  end
  array
end

puts "Enter Array size: "
size = gets.chomp
start_array = generate_array(size)
puts "Start Array  = #{start_array.join(" ~ ")} "
result = insert_zeros_to_array(start_array)
puts "Result Array = #{result.join(" ~ ")} "