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mikedao/credit_check.rb

Created December 17, 2014 06:02
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Luhn's Algorithm
Raw
credit_check.rb
def validator(card)
card.chars
.map { |n| n.to_i }
.map.with_index { |n, index| index.even? ? n * 2 : n }
.map { |n| n.to_s.length == 2 ? n.to_s[0].to_i + n.to_s[1].to_i : n }
.reduce(:+) % 10 == 0 ? "Valid" : "Invalid"
end
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