Check if a credit card number is valid or not.

Credit_Check.rb

require 'pry'
puts "Please enter a 16 digit credit card number for validation."
this = gets.chomp
card_number = this.reverse
# 
unless card_number.length. == 16
    puts "Requires 16 digits"
    load 'credit_check.rb'
end

card_array = card_number.split("")

# puts card_array.to_s

q = (card_number[0])
j = (card_number[2])
k = (card_number[4])
l = (card_number[6])
m = (card_number[8])
n = (card_number[10])
o = (card_number[12])
p = (card_number[14])
new_card_array = [q.to_i, j.to_i, k.to_i, l.to_i, m.to_i, n.to_i, o.to_i, p.to_i]
a = (card_number[1].to_i)*2
b = (card_number[3].to_i)*2
c = (card_number[5].to_i)*2
d = (card_number[7].to_i)*2
e = (card_number[9].to_i)*2
f = (card_number[11].to_i)*2
g = (card_number[13].to_i)*2
h = (card_number[15].to_i)*2

# puts "------------------------"

if a >= 10
    aa = a.to_s[0]
    ab = a.to_s[1]
    ac = aa.to_i
    ad = ab.to_i
    ae = (ac + ad)
    new_card_array.insert(1, ae.to_i)
 else
  new_card_array.insert(1, a.to_i)
end
if b >= 10
    ba = b.to_s[0]
    bb = b.to_s[1]
    bc = ba.to_i
    bd = bb.to_i
    be = (bc + bd)
    new_card_array.insert(3, be.to_i)
 else
  new_card_array.insert(3, b.to_i)
end
if c >= 10
    ca = c.to_s[0]
    cb = c.to_s[1]
    cc = ca.to_i
    cd = cb.to_i
    ce = (cc + cd)
    new_card_array.insert(5, ce.to_i)
 else
   new_card_array.insert(5, c.to_i)
end
if d >= 10
    da = d.to_s[0]
    db = d.to_s[1]
    dc = da.to_i
    dd = db.to_i
    de = (dc + dd)
    new_card_array.insert(7, de.to_i)
 else
  new_card_array.insert(7, d.to_i)
end
if e >= 10
    ea = e.to_s[0]
    eb = e.to_s[1]
    ec = ea.to_i
    ed = eb.to_i
    ee = (ec + ed.to_i)
    new_card_array.insert(9, ee.to_i)
 else
  new_card_array.insert(9, e.to_i)
end
if f >= 10
    fa = f.to_s[0]
    fb = f.to_s[1]
    fc = fa.to_i
    fd = fb.to_i
    fe = (fc + fd)
    new_card_array.insert(11, fe.to_i)
 else
  new_card_array.insert(11, f.to_i)
end
if g >= 10
    ga = g.to_s[0]
    gb = g.to_s[1]
    gc = ga.to_i
    gd = gb.to_i
    ge = (gc + gd)
    new_card_array.insert(13, ge.to_i)
 else
  new_card_array.insert(13, g.to_i)
end
if h >= 10
    ha = h.to_s[0]
    hb = h.to_s[1]
    hc = ha.to_i
    hd = hb.to_i
    he = (hc + hd)
    new_card_array.insert(15, he.to_i)
 else
  new_card_array.insert(15, h.to_i)
end

# puts "-------------"

# puts new_card_array.to_s

total = new_card_array.reduce(0) {|sum, i|  sum + i }

# puts total

if total % 10 == 0
    puts "This number is Valid!"
    valid = true
else
    puts "This number is Invalid!"
    valid = false
end

puts "Do you have another number? (y/n)"
user_input = gets.chomp

if user_input == "n" 
    abort
elsif user_input == "y" 
    load 'credit_check.rb'
elsif user_input == "Y"
    load 'credit_check.rb'
elsif user_input == "N"
    abort
else
    puts "You did not enter (y/n) program will now close."
    abort
end