Compilare: user.cpp: In function ‘int main()’: user.cpp:35:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<it->second.size();i++){ ^ user.cpp:21:26: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%lld",&n); ^ user.cpp:25:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%lld",&x); ^