Compilare: user.cpp: In function ‘int main()’: user.cpp:58:14: warning: variable ‘fo’ set but not used [-Wunused-but-set-variable] FILE*fi,*fo; ^~ user.cpp:63:30: 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:65:44: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d%d", &v[i].x, &v[i].y); ^