Compilare: user.cpp: In function ‘int main()’: user.cpp:30:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0;j<V[current].size();j++) ^ user.cpp:9:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.in","r",stdin); ^ 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("sortaret.out","w",stdout); ^