Problem 6-Sum square difference

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;
int main(){
int val = 0, sum1 = 0, sum2 = 0;
for(int i = 1; i <= 100; i++){
sum1 += i*i;
sum2 += i;
}
val = sum1 - sum2 * sum2;
cout<<val<<endl;
return 0;
}