Module: Pmt::Primes

Defined in:
lib/pmt/primes.rb

Class Method Summary collapse

Class Method Details

.first(n) ⇒ Object 



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# File 'lib/pmt/primes.rb', line 5

def self.first(n)
  raise "Number of primes should be an integer" unless n.is_a? Integer
  raise "Number of primes needs to be a positive number" if n < 1

  counter = 2
  number_of_primes_found = 0
  primes = []

  while number_of_primes_found < n
    if is_prime_number(counter)
      primes << counter
      number_of_primes_found += 1
    end
    counter += 1
  end

  primes
end

.is_prime_number(num) ⇒ Object 



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# File 'lib/pmt/primes.rb', line 24

def self.is_prime_number(num)
  return true if num > 1 && num < 4
  sqrt = Math.sqrt(num).to_i
  (2..sqrt).each do |diviser|
    if num % diviser == 0
      return false
    end
  end
  true
end