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@davidbella
Created October 1, 2013 20:42
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Ruby: Simple prime number solution in Ruby
def prime?(number)
tries = 0
i = 5
prime = true
return false if number.even? || number % 3 == 0 || number < 2
while (i*i) < number
tries += 1
prime = false and break if number % i == 0
i += 2
end
prime_in_words = prime ? "prime" : "not prime"
prime
puts "#{number} is #{prime_in_words}."
puts "...solved in #{tries} tries"
end
prime? 8
prime? 11
prime? 119
prime? 2541
prime? 12124
prime? 10007
prime? 5788516110007
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