单链表（非循环）倒数第4个元素

思路：让第一个元素先走四步，然后两个游标指针一起走。

node*Get_Node(node *head)

{

inti;

node*first = head;

node*back  = head;

 

for(i=0;i<4; i++)

{

if(first->next== NULL)

printf("Nodeless than four!\n");

first= first->next;

}

while(first!= NULL)

{

first= first->next;

back= back->next;

}

returnback;

}