Compilare: user.c: In function ‘det’: user.c:13: warning: implicit declaration of function ‘isdigit’ user.c: In function ‘main’: user.c:38: warning: unused variable ‘nr’ user.c:42: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result user.c:43: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result user.c:47: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result