Compilare: user.cpp: In function ‘std::string div(std::string, int)’: user.cpp:28:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.length(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:58:10: warning: unused variable ‘ok’ [-Wunused-variable] bool ok; ^ user.cpp:59:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("quadratum.in","r",stdin); ^ user.cpp:60:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("quadratum.out","w",stdout); ^