Compilare: user.cpp: In function ‘int main()’: user.cpp:32:33: warning: format ‘%lf’ expects argument of type ‘double’, but argument 3 has type ‘long double’ [-Wformat=] fprintf(out, "%.5lf\n", AREA); ^ user.cpp:24:25: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d", &N); ^ user.cpp:26:48: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%lf %lf", &P[i].x, &P[i].y); ^