Compilare: main.cpp: In function 'bool isPrime(llui)': main.cpp:99:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (x == 1 or x == n - 1) ~~^~~~~~~~ main.cpp:101:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < s and x != n - 1; ++i) ~~^~~ main.cpp:101:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < s and x != n - 1; ++i) ~~^~~~~~~~ main.cpp:103:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (x != n - 1) ~~^~~~~~~~ main.cpp: In function 'int main()': main.cpp:166:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("overpower.in", "r", stdin); ^ main.cpp:167:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("overpower.out", "w", stdout); ^