Quick'n'dirty prime number calculation

primes.c

#include <iostream>
#include <vector>
#include <math.h> 

int main()
{
    std::vector<long> primes;
    primes.push_back(2);
    for(long i=3; i < 2^63; i++)
    {
        bool prime=true;
        for(long j=0;j<primes.size() && primes[j]*primes[j] <= i;j++)
        {
            if(i % primes[j] == 0)
            {
                prime=false;
                break;
            }
        }
        if(prime) 
        {
          primes.push_back(i);
          std::cout << i << " ";
        }
    }

    // std::cout << primes.size() << " ";

    return 0;
}

primes.rb

#!/usr/bin/ruby

primes = [2]

3.upto(1000000) { |i|
  prime = true
  0.upto(primes.length) { |j|
    if (i%primes[j]==0) then
      prime = false
      break
    end
    break if (primes[j]*primes[j]>i)
  }
  if prime
    primes.push(i) 
    print "#{i} "
  end
}