Compilare: user.cpp: In constructor ‘numar::numar(std::string)’: user.cpp:47:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int poz = 0 ; poz < s.size() ; ++ poz) ^ user.cpp: In function ‘int main()’: user.cpp:384:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < ex.size() ; ++ i) ^ user.cpp:358:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("eval.out","w",stdout); ^