欧拉计划 第6题

The sum of the squares of the first ten natural numbers is,

1² + 2² + ... + 10² = 385

The square of the sum of the first ten natural numbers is,

(1 + 2 + ... + 10)² = 55² = 3025

Hence the difference between the sum of the squares of the first ten natural numbers and the square of the sum is 3025 385 = 2640.

Find the difference between the sum of the squares of the first one hundred natural numbers and the square of the sum.

 long sumOfSquares = 0;
            for (int i = 1; i <= 100; i++)
            {
                sumOfSquares += (long)Math.Pow(i, 2);
            }

            long sum = 0;
            for (int i = 1; i <= 100; i++)
            {
                sum += i;
            }
            long squaresOfSum = (long)Math.Pow(sum,2);
            Console.WriteLine("{0}-{1}={2}", squaresOfSum, sumOfSquares, squaresOfSum - sumOfSquares);