Problem 10.cs

using System;

namespace ProjectEuler
{
    class Problem_10
    {
        /*
         * The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.
         *
         * Find the sum of all the primes below two million.
         */

        public static void Run()
        {
            int number = 2000000;
            long sum = 2;

            for (int divisor = 3; divisor < number; divisor += 2)
            {
                bool isPrime = true;

                for (int index = 3; index < Math.Sqrt(divisor); index += 2)
                    if (divisor % index == 0)
                    {
                        isPrime = false;
                        break;
                    }

                if (isPrime)
                    sum += divisor;
            }

            Console.WriteLine(sum);
            Console.ReadKey();
        }
    }
}