Compilare: user.cpp: In function ‘int main()’: user.cpp:15:14: warning: variable ‘fo’ set but not used [-Wunused-but-set-variable] FILE*fi,*fo; ^~ user.cpp:20:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d%d", &n, &m); ^ user.cpp:22:48: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%lld%lld", &v[i].x, &v[i].y); ^