Compilare: main.c: In function 'main': main.c:18:2: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("euclid2.in", "r", stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:19:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("euclid2.out", "w", stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:21:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%ld", &n); ^~~~~~~~~~~~~~~~ main.c:24:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf( "%ld%ld" , &x , &y ) ; ^~~~~~~~~~~~~~~~~~~~~~~~~~~