Compilare: user.c: In function ‘main’: user.c:18: warning: unused variable ‘p’ user.c:18: warning: unused variable ‘l’ user.c:12: warning: unused variable ‘used’ user.c:7: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:8: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result user.c:15: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result