Compilare: user.c: In function ‘main’: user.c:18: warning: operation on ‘x’ may be undefined user.c:10: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:11: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:12: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result user.c:16: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result