Compilare: user.c: In function ‘main’: user.c:16:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("rucsac.in", "r", stdin); ^ user.c:17:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("rucsac.out", "w", stdout); ^ user.c:18:7: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &g); ^ user.c:20:8: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &v[i].w, &v[i].p); ^