Compilare: user.c: In function ‘read’: user.c:28:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen(FIN , "r", stdin); ^ user.c:30:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld", &N); ^ user.c:34:22: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld", &mat[ i ][ j ]); ^ user.c: In function ‘write’: user.c:60:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen(FOUT, "w", stdout); ^