Compilare: user.c: In function ‘C’: user.c:8:12: warning: operation on ‘a[r]’ may be undefined [-Wsequence-point] a[r]^=a[p]^=a[r]^=a[p]; ^ user.c:13:17: warning: operation on ‘a[l]’ may be undefined [-Wsequence-point] a[l]^=a[j]^=a[l]^=a[j]; ^ user.c:16:14: warning: operation on ‘a[l + 1]’ may be undefined [-Wsequence-point] a[l+1]^=a[r]^=a[l+1]^=a[r]; ^ user.c: In function ‘main’: user.c:20:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("sdo.in","r",stdin),freopen("sdo.out","w",stdout),scanf("%d%d%d",&n,&k,&a[1]); ^ user.c:20:37: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("sdo.in","r",stdin),freopen("sdo.out","w",stdout),scanf("%d%d%d",&n,&k,&a[1]); ^ user.c:20:65: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("sdo.in","r",stdin),freopen("sdo.out","w",stdout),scanf("%d%d%d",&n,&k,&a[1]); ^ user.c:22:8: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a[i]); ^