Compilare: main.cpp: In function 'int main()': main.cpp:34:31: warning: format '%lf' expects argument of type 'double', but argument 3 has type 'long double' [-Wformat=] fprintf (fout, "%.8lf", s/2 ) ; ^ main.cpp:23:27: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin, "%d", &n ) ; ^ main.cpp:25:48: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin, "%lf %lf", &v[i].x, &v[i].y ) ; ^