Compilare: user.c: In function ‘main’: user.c:19:7: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(v[i-1]) ^ user.c:10:15: warning: variable ‘a’ set but not used [-Wunused-but-set-variable] int i,n,x,r=0,a; ^ user.c:11:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&n); ^ user.c:14:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&x); ^