Compilare: user.cpp: In function ‘int main()’: user.cpp:34:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<v[x].size(); i++) ^ user.cpp:20:29: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d%d",&n,&m); ^ user.cpp:24:38: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d%d%d",&a,&b,&c); ^