Compilare: user.cpp: In function ‘int main()’: user.cpp:49:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i < s.size();i ++) ^ user.cpp:43:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spion.in","r",stdin); ^ user.cpp:44:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spion.out","w",stdout); ^