Compilare: user.cpp: In function ‘void desc(long long int)’: user.cpp:31:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < pr.size() && pr[i] * pr[i] <= n) { ^ user.cpp: In function ‘int main()’: user.cpp:57:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ssnd.in","r",stdin); ^ user.cpp:58:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ssnd.out","w",stdin); ^