Project Euler problem #6 solution.

using System;

public class Six
{
    static void Main()
    {
        double a = 100;
        double b = 0;
        double c = 0;

        for (int i = 1; i <= a; i++)
        {
            b += (i * i);
            c += i;
        }

        c = c * c;

        if (b > c)
            Console.WriteLine("\n{0}\n", b - c);
        else if (c > b)
            Console.WriteLine("\n{0}\n", c - b);
    }
}