Compilare: user.c: In function ‘main’: user.c:17:24: warning: unused variable ‘x’ [-Wunused-variable] long int n, i, a, b, x; ^ user.c:22:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%ld", &n); ^ user.c:25:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%ld %ld", &a, &b); ^