从键盘上输入一批非零整数，采用带头结点的单链表存放，
将单链表中的所有正数放在链表的前面，所有负数放在后面，
并将单链表输出

你可以先定义一个值为0的链表节点

大于0的方前面

小于0的放后面

完了删除0节点就ok了

吃鹅吃柳又爱我吧
#include <stdio.h>
#include <stdlib.h>
struct list{
    int data;
    struct list *next;
};
typedef struct list  p;
typedef p *pnext;

void insert(pnext head,int d)
{
   pnext newnode,phead,ptr;
   phead=head;
   
   newnode=(pnext)malloc(sizeof(p));
   newnode->data=d;
   if(phead->next==NULL)
   {
       phead->next=newnode;
       newnode->next=NULL;
   }
   else if(d>0)
   {
     newnode->next=phead->next;
     phead->next=newnode;
   }
   else
   {  ptr=head;
      while(ptr->next!=NULL)
         ptr=ptr->next;
        
        ptr->next=newnode;
        newnode->next=NULL;
   }
}
void pfree(pnext head)
{    pnext ptr;
    while(head->next!=NULL)
    {    ptr=head;
    head=head->next;
       free(ptr);
    }  
}
void main()
{
  int d;   
  pnext head;
  pnext ptr;
  printf("please input datas,input -1 end\n");
  head=(pnext)malloc(sizeof(p));
  head->next=NULL;
  do{
      scanf("%d",&d);
      insert(head,d);
  }while(d!=-1);
   
  ptr=head;
  while(ptr->next!=NULL)
  {printf(" %d ",ptr->next->data);
      ptr->next=ptr->next->next;
  }
  pfree(head);
}

struct _node
{
    long data;
    _node *next;
};

bool InsertList(_node **_head,_node **_tail,long _data)
{
    if(_head == NULL || _tail == NULL)
        return false;
    _node *p;
    p = (_node*)malloc(sizeof(_node));
    p->data = _data;
    if(_data > 0)
    {
        p->next = *_head;
        *_head = p;
    }
    else
    {
        p = (_node*)malloc(sizeof(_node));
        p->data = _data;
        (*_tail)->next = p;
        p->next = NULL;
        *_tail = p;
    }
    return true;
}

int main(int argc, char* argv[])
{
    _node *head,*tail,*p,*temp;
    long int data;
    head = (_node*)malloc(sizeof(_node));
    head->next = NULL;
    printf("please input the first node:");
    scanf("%d",&head->data);
    tail = head;
    do
    {
        printf("please insert a node:");
        scanf("%d",&data);
        if(data)
        {
            InsertList(&head,&tail,data);
        }
    } while (data);
    p = head;
    while(p != NULL)
    {
        printf("%d\t",p->data);
        temp = p;
        p = p->next;
        free(temp);
    }
    return 0;
}