（Problem 6）Sum square difference

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.

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <math.h>

#define N 100

int powplus(int n, int k)
{
int s=1;
while(k--)
{
s*=n;
}
return s;
}

int sum1(int n)
{
return  powplus((n+1)*n/2,2);
}

int sum2(int n)
{
return (n*(n+1)*(2*n+1))/6;
}

void solve()
{
printf("%d\n",sum1(N));
printf("%d\n",sum2(N));
printf("%d\n",sum1(N)-sum2(N));
}

int main()
{
solve();
return 0;
}

Answer:

25164150