Compilare: main.c: In function 'main': main.c:12:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("gfact.in", "r", stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:13:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("gfact.out", "w", stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:15:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &p); ^~~~~~~~~~~~~~~~ main.c:16:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &q); ^~~~~~~~~~~~~~~