Compilare: user.c: In function ‘euclid’: user.c:13:5: warning: type of ‘a’ defaults to ‘int’ [enabled by default] int euclid(a, b) { ^ user.c:13:5: warning: type of ‘b’ defaults to ‘int’ [enabled by default] user.c: In function ‘solve’: user.c:26:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmmdc.in", "r", stdin); ^ user.c:27:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmmdc.out", "w", stdout); ^ user.c:29:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &a, &b); ^