void reverselist(void)

{

if(head==0)

return;

if(head-<next==0)

return;

if(head-<next==tail)

{

head-<next = 0;

tail-<next = head;

}

else

{

node* pre = head;

node* cur = head-<next;

node* curnext = cur-<next;

head-<next = 0;

cur-<next = head;

for(; curnext!=0; )

{

cur-<next = pre;

pre = cur;

cur = curnext;

curnext = curnext-<next;

}

curnext-<next = cur;

}

}