Compilare: user.c: In function ‘main’: user.c:52: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:53: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:55: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result user.c:64: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result