Compilare: user.c:13:15: warning: conflicting types for built-in function ‘abs’ [enabled by default] inline double abs(double x){ ^ user.c: In function ‘main’: user.c:52:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d", &n); ^ user.c:54:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%lf%lf", &x[i], &y[i]); ^ user.c:62:7: warning: ‘p’ may be used uninitialized in this function [-Wmaybe-uninitialized] aux = y[p]; y[p] = y[0]; y[0] = aux; ^