Learning Ruby 2.1 Warmup 1: Random Number Generator

# Aaron Greenlee
# http://aarongreenlee.com/
# Activity 2.1: Warmup 1

MIN_N = 1
MAX_N = 1000000
STOP_GOING = ['no','n']
KEEP_GOING = ['yes','y']
GOOD_GOING_ANSWERS = KEEP_GOING | STOP_GOING
GOOD_GOING_ANSWERS_STRING = "'" + GOOD_GOING_ANSWERS.join('", "') + '"'
valid = false
#
# We should greet the user
#
puts "Hello and welcome to the warmup random generator (WRG)."
#
# Accept input from the user
#
begin
  valid = good_rangeA = good_rangeB = false

  puts "\nPlease give me a minimum and maximum number, separated by a comma (ex: 1,40) between 1 and 1,000,000."
  print "What are the min,max numbers? : "
  input = gets.chomp.split(',')

  good_format = input.length == 2

  if !good_format
    puts "\nYou need two numbers separated by a comma!"
  else
    min_n = input[0].to_i
    max_n = input[1].to_i

    good_rangeA = (min_n < max_n) && min_n.between?(MIN_N,MAX_N)
    good_rangeB = (max_n > min_n) && max_n.between?(MIN_N,MAX_N)

    puts "\nThe min (#{min_n}) is greater than the max (#{max_n})!" if !good_rangeA
    puts "\n1The max (#{max_n}) is less than the min (#{min_n})!" if !good_rangeB
  end
  valid = good_format && good_rangeA && good_rangeB
end while not valid
#
# How many random numbers should be generated?
#
valid = false
begin
  print  "\n\nHow many random numbers would you like? : "
  qty = gets.chomp.to_i
  valid = qty > 0
  puts "\nThat makes no sense. I need a number--and a number of at least one. Could be more." if !valid
end while not valid
#
# Generate the numbers
#
result = []
i = 0
(1..qty).each {
  i += 1
  rnum = rand(max_n - min_n + 1) + min_n
  result << rnum
}
final_result = result.sort
#
# Show the numbers at least once but as often as they like
#
show_again = true
begin
  puts "Your random numbers are : " + final_result.join('; ') + ";"
  
  valid = false
  begin
    puts "\nWould you like to see them again? (" + GOOD_GOING_ANSWERS_STRING + ') : '
    input = gets.strip.chomp
    valid = GOOD_GOING_ANSWERS.include? input
    puts "Allowed answers are " + GOOD_GOING_ANSWERS_STRING + "! Please clarify." if !valid
  end while not valid

  show_again = KEEP_GOING.include? input

end while show_again

puts "\nThanks for your time.\n"