欧拉计划 第一题

 If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9.

 The sum of these multiples is 23.

 Find the sum of all the multiples of 3 or 5 below 1000.  

            long result = 0;
            for (int i = 0; i < 1000; i++)
            {
                if (i%3 == 0 || i%5 == 0) result += i;
            }
            Console.WriteLine(result);