Compilare: user.c: In function ‘M’: user.c:10:30: warning: operation on ‘a[i]’ may be undefined [-Wsequence-point] l=(l+m-i+1)%9917,a[i]^=a[j]^=a[i]^=a[j]; ^ user.c: In function ‘main’: user.c:13:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("inv.in","r",stdin),freopen("inv.out","w",stdout),scanf("%d",&n); ^ user.c:13:40: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("inv.in","r",stdin),freopen("inv.out","w",stdout),scanf("%d",&n); ^ user.c:13:68: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("inv.in","r",stdin),freopen("inv.out","w",stdout),scanf("%d",&n); ^ user.c:15:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",a+i); ^