ProjectEuler_P6

Question：

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.

 

C Code：

#include <stdio.h>

void main()
{
　　int i;
　　int sum1 = 0;
　　int sum2 = 0;
　　for(i = 1;i <= 100;i++)
　　{
　　　　sum1 += i*i;
　　　　sum2 += i;
　　}
　　printf("%d\n",sum2*sum2 - sum1);
}

 

Answer：

25164250