Compilare: user.cpp: In function ‘int main()’: user.cpp:103:20: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘long long int’ [-Wformat=] printf("%d\n", ans); ^ user.cpp:75:51: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen((file_input + ".in").c_str(), "r", stdin); ^ user.cpp:76:53: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen((file_input + ".out").c_str(), "w", stdout); ^