Compilare: user.c: In function ‘join’: user.c:7:5: warning: implicit declaration of function ‘tata’ [-Wimplicit-function-declaration] t[x] = tata(y); ^ user.c: In function ‘main’: user.c:24:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("disjoint.in", "r", stdin); ^ user.c:25:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("disjoint.out", "w", stdout); ^ user.c:27:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.c:30:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &op, &x, &y); ^