Compilare: user.c: In function ‘main’: user.c:40:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("royfloyd.in", "r", stdin); ^ user.c:41:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("royfloyd.out", "w", stdout); ^ user.c:43:7: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.c:47:9: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &C[i][j]); ^