Compilare: user.c: In function ‘main’: user.c:21:20: warning: unused variable ‘div’ [-Wunused-variable] int t,i,x,e,xc,div,j; ^ user.c:21:17: warning: unused variable ‘xc’ [-Wunused-variable] int t,i,x,e,xc,div,j; ^ user.c:21:15: warning: unused variable ‘e’ [-Wunused-variable] int t,i,x,e,xc,div,j; ^ user.c:22:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("sum.in","r",stdin); ^ user.c:23:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("sum.out","w",stdout); ^