Compilare: user.c: In function ‘main’: user.c:44: warning: ' ' flag used with ‘%u’ gnu_printf format user.c:46: warning: unknown conversion type character 0xa in format user.c:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:13: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:16: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result user.c:22: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result