Compilare: user.cpp: In function ‘int main()’: user.cpp:20:10: warning: statement has no effect [-Wunused-value] for(m;m>0;m--){ ^ user.cpp:30:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<v[i].size();j++){ ^ user.cpp:18:38: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d%d%d",&n,&m,&start); ^ user.cpp:21:33: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d%d",&i,&j); ^