Compilare: main.c: In function 'main': main.c:6:2: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("euclid2.in", "r", stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:7:6: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("euclid2.out", "w", stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:8:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^~~~~~~~~~~~~~~ main.c:10:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%li %li", &a, &b); ^~~~~~~~~~~~~~~~~~~~~~~~