/** * \file * \brief [Problem 6](https://projecteuler.net/problem=6) solution */ #include /** Main function */ int main(void) { unsigned s1 = 0, s2 = 0, i; for (i = 1; i <= 100; i++) { s1 += i * i; s2 += i; } unsigned ans = s2 * s2 - s1; printf("%u\n", ans); return 0; }