#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include <string.h>
#define ID struct id
struct id
  {
   char name[20];
   int num;
   char price[20];
   char sum[20];
   ID *next;
  }Market;
struct id *head=NULL;
int pc=0;
void save();
int read();
ID *creat()
{
  ID *p1,*p2,*head;
  int pd;
  p1=p2=head=NULL;
  printf("请输入数字(0为终止符)!\n");
  printf("*********************************************************\n");
  while(1)
  {
   printf("请输入商品编号:\n");scanf("%d",&pd);
   if(pd==0) break;
   p1=(ID*)malloc(sizeof(ID));
   p1->num=pd;
   printf("请输入商品名称:\n");scanf("%s",p1->name);
   printf("请输入商品单价:\n");scanf("%s",p1->price);
   printf("请输入商品总量:\n");scanf("%s",p1->sum);
   if(head==NULL)
   {
     head=p1;
     p2=p1;
   }
   else
   {
     p2->next=p1;
     p2=p1;
   }
   pc++;
  }
  p2->next=NULL;
  return(head);
 }
 ID *insert(ID *head)
 {
  ID *temp,*p1,*p2;
  printf("开始插入!!!\n");
  temp=(ID *)malloc(sizeof(ID));
  printf("请输入商品编号:\n");scanf("%d",&temp->num);
  printf("请输入商品名称:\n");scanf("%s",temp->name);
  printf("请输入商品单价:\n");scanf("%s",temp->price);
  printf("请输入商品总量:\n");scanf("%s",temp->sum);
  if(head==NULL)
  {
   head=temp;
   temp->next=NULL;
  }
  else
  {
   p1=head;
   while(p1!=NULL)
   {
     p2=p1;
     p1=p1->next;
   }
   p2->next=temp;
   temp->next=p1;
  }
  printf("成功插入!");
  pc++;
  return(head);
 }
 ID *delet(ID *head)
 {
  ID *p1,*p2;
  int num;
  printf("请输入要删除货物的编号:");scanf("%d",&num);
  p1=head;
  if(head==NULL)
  {
   printf("无历史纪录\n");
   goto end;

  }
  while(num!=p1->num&&p1!=NULL)
  {
   p2=p1;p1=p1->next;
  }
  if(num==p1->num)
  {
   if(p1==head)
   head=p1->next;
   else
   p2->next=p1->next;
   printf("成功删除!!!\n");
   pc--;
  }
  end:return head;
 }
 ID *search_name(ID *head)
 {
  ID *p1,*p2;
  char str[100];
  printf("请输入要查找货物的编号:");scanf("%s",str);
  p1=head;
  while(strcmp(str,p1->name)&&p1!=NULL)
  {
   p2=p1;p1=p1->next;
  }
  if(strcmp(str,p1->name)==0)
  {
   printf("商品编号:%d\n",p1->num);
   printf("商品名称:%s\n",p1->name);
   printf("商品单价:%s\n",p1->price);
   printf("商品总量:%s\n",p1->sum);
  }
  return head;
 }
 ID *search_num(ID *head)
 {
  int num;
  ID *p1,*p2;
  printf("请输入要货物的编号:");scanf("%d",&num);
  p1=head;
  while(num!=p1->num&&p1!=NULL)
  {
   p2=p1;p1=p1->next;
  }
  if(num==p1->num)
  {
   printf("商品编号:%d\n",p1->num);
   printf("商品名称:%s\n",p1->name);
   printf("商品单价:%s\n",p1->price);
   printf("商品总量:%s\n",p1->sum);
  }
  return head;
 }
 ID *search(ID *head)
 {
   int mode;
   ID *h;
   printf("请选择搜索方式:方法1.num  方法2.name\n");
   scanf("%d",&mode);
   if(mode==1)
   h=search_num(head);
   else if(mode==2)
   h=search_name(head);
   else
   printf("输入错误!\n");
   return h;
   }
   void print(ID *head)
   {
    ID *p;
    p=head;
    printf("\t\t\t******************\n");
    printf("结果列表显示 :\n");
    if(head!=NULL)
    do
    {
     printf("编号%-10d 名称%-10s 单价%-10s 总量%-10s\n",p->num,p->name,p->price,p->sum);
     p=p->next;
    }while(p!=NULL);
   }
void save()//保存收入
{
   
    FILE *fp;
    if((fp=fopen("d:\\market.din","wb"))==NULL)
    {
        printf("cannot open file\n");
        exit(1);
    }
    fwrite(&head,sizeof(int),1,fp);
    if(fwrite(Market,sizeof(struct  id),4,fp)!=4)
    printf("file write error");
     fclose(fp);   
}
int read()
{
    FILE *fp;
    if((fp=fopen("d:\\market.din","rb"))==NULL)
    {
        return 1;
    }
    fread(&head,sizeof(int),1,fp);
    if(fread(Market,sizeof(struct  id),4,fp)!=4)
    {
        printf("read error");
        exit (1);}
        fclose(fp);
}

   void main()
   {
     ID *head=NULL;
     int choise;
     head=read();
     printf("\t\t*****大型仓库管理系统*****\n");
     while(1)
     {
      printf("\t\t   商品管理系统公测版本\n");
      printf("|*********************************************************|\n");
      printf("|**|                        1.输入                     |**|\n");
      printf("|**|                       2.显示                      |**|\n");
      printf("|**|                       3.搜索                      |**|\n");
      printf("|**|                       4.插入                      |**|\n");
      printf("|**|                       5.删除                      |**|\n");
      printf("|**|                        0.退出                     |**|\n");
      printf("|*********************************************************|\n");
      printf("请选择服务项目(0-6):");
      scanf("%d",&choise);
      switch(choise)
      {
       case 1:head=creat();
       break;
       case 2:print(head);
       break;
       case 3:head=search(head);
       break;
       case 4:head=insert(head);
       break;
       case 5:head=delet(head);
       break;
       case 0:
       exit(0);
       break;
       default:printf("输入错误! 请重新输入!\n");
      }
     }save ();
    }

楼主！！！
问题一：你save()中把链表的头指针也写入文件中根本就没有什么用！！！！因为程序一结束你之前的＊head所指向的地址就会被释放。
问题二：fread(),fwrite()的第一个参数是接收/输出数据的地址的，如果我没理解错的话Market是一个变量吧！！
问题三：你read()函数中你一下子就从文件中读取4个你是往哪存的呀！！！！

解决方法：在save中第一个要写入文件的是你要存的结构体结点的个数（方便读取），然后再把你的所有结点写进去。在read的时候先读的就是你总结点数然后用一个循环每读一个结点就把它接到链表上。这样就OK啦！！！

说实话，我们链表知识讲的不大理解！求具体的源程序！

哦