Compilare: user.cpp: In function ‘int main()’: user.cpp:20:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; (long long)(1 << i) <= n; ++i){ ^ user.cpp:10:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("algebra2.in", "r", stdin); ^ user.cpp:11:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("algebra2.out", "w", stdout); ^ user.cpp:12:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &n); ^