Calculate the sum of prime numbers below a maximum number of integers (max_prime). This is in response to the Project Euler Problem 10: http://projecteuler.net/problem=10 This problem states to find the sum of all prime numbers less than 2,000,000.

gistfile1.rb

max_prime = 51

array = Array.new(max_prime) { |i| i }
not_primes = []
primes = []

array.each do |i|    
  if i > 1 && i <= (max_prime ** 0.5)
    0.upto(max_prime) do |j|
      sieve = i**2 + (j * i) # Sieve_of_Eratosthenes algorithm to find non-primes
      if sieve > max_prime
        break
      elsif not not_primes.include? sieve
        not_primes << sieve
      end
    end
  end
end

array.each { |i| primes << i if not not_primes.include? i } 
primes.shift(2)

puts primes.inject(:+)
primes.inject(:+)