返回单链表的倒数第n个节点

struct list_node

{

struct list_node  *next;

void *data;

};

struct list_node  *get_last_nth_node(struct list_node *head, unsigned int pos)

{

struct list_node *ret = head;

unsigned int i = 0;

while(head && i < pos)

{

++i;

head = head->next;

}

if(!head)

{

return NULL;

}

while(head->next)

{

ret = ret ->next;

head = head->next;

}

return ret;

}