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

Question

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. I have the following code but the answer do

Answer 1

int main(int argc, char** argv)
{
    unsigned int count = 0;
    for(int i = 1; i < 1001; ++i)
        if(!(i % 3) && !(i % 5))
            count += i;
    std::cout << i;
    return 0;
}