Compilare: user.c: In function ‘read_data’: user.c:34:20: warning: unused variable ‘minus’ [-Wunused-variable] int i, ind, x, minus; ^ user.c:36:5: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &N, &K); ^ user.c:37:5: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result [-Wunused-result] fgets(sir, 1<<22, stdin); ^ user.c: In function ‘main’: user.c:63:5: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("secventa.in", "rt", stdin); ^ user.c:64:5: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("secventa.out", "wt", stdout); ^