#include <stdio.h>
#include <stdlib.h>
struct data
{
    int num;
   

};
struct student
{
    struct data dat;
    struct student *next;

};
struct student *lianbiao()
{
    FILE *fp;
    fp=fopen("1.txt","r+");
    if(NULL == fp)        
        {
            printf("文件读取失败!");
            exit(1);          //非0为非正常退出   

        }
    struct student *head=(struct student *)malloc(sizeof(struct student));
    struct data asd;
    head->next=NULL;
   
    while(0!=fread(&asd,sizeof(struct data),1,fp));
    {
        struct student *p=(struct student *)malloc(sizeof(struct student));
        p->dat=asd;
        p->next=NULL;
        p->next=head->next;
        head->next=p;
   
    }
    fclose(fp);   
    return head;


}
struct student *print(struct student *head)
{
    struct student *p=head->next;
    while(p!=NULL)
    {
        printf("%d",p->dat.num);
        p=p->next;
   
    }


}
struct student *add()
{
    struct student *head=lianbiao();
//    struct student *head=(struct student *)malloc(sizeof(struct student));
    while(1)
    {   
        char m;
        struct student *p=(struct student *)malloc(sizeof(struct student));
        printf("请输入添加的数据：");   
        scanf("%d",&p->dat.num);
        getchar();
        p->next=head->next;
        head->next=p;
        printf("是否继续添加Y or N");
        scanf("%c",&m);
        getchar;
        if(m=='n'&&'N')
        {   
            break;
        }
    }
    return head;
}
void main()
{   
    FILE *fp;
    fp=fopen("1.txt","w+");
    struct student *head=(struct student *)malloc(sizeof(struct student));
    head=add();
    struct student *p=(struct student *)malloc(sizeof(struct student));
    p=head;
    while(p!=NULL)
    {
        fwrite(&p->dat,sizeof(struct student),1,fp);
        p=p->next;
   
    }
    print(head);
    fclose(fp);
}

老是出问题指的是出什么问题？

有点乱
malloc不能随便用，用完之后就要free掉
链表最好定义一对全局可见的首尾指针，这样能更好操作链表。

就是链表里的数据存不到文件里面去。

嗯，确实很乱。刚开始学习这个，我感觉就是读取或者写入文件的时候有问题。

[此贴子已经被作者于2016-6-4 00:03编辑过]

问题有不少
我随便提几个

1.lianbiao函数中读循环while后有分号
2.你的流程是程序开始后以w+模式打开文件,这意味着清空文件,也就是每次启动程序文件都会被清空.
3.流程接近结束时往文件写入模块以struct student为size做参数写入的确实struct data
4.main下每次都为head malloc了东西但又立马使用add的返回值作为head，内存泄露

简单改编了一下之前一位同学的代码，作为示例参考。

/*
    数据表
*/
#include <stdio.h>
#include <stdlib.h>
#include <io.h>
#include <string.h>

typedef struct _TABLE_
{
    unsigned int dwID;  //ID
    char szNumber[10];  //编号
    char szName[30];    //姓名
    char szGender[10];  //性别
    char Age;           //年龄
    char szLevel[10];   //级别
    double qwScore;     //评分
} TABLE, *PTABLE;

typedef struct _TABLE_LIST_
{
    TABLE stTable;
    struct _TABLE_LIST_ *lpPrior, *lpNext;
} TABLELIST, *PTABLELIST;

PTABLELIST lpTop    = NULL;     //表首指针
PTABLELIST lpBottom = NULL;     //表尾指针
PTABLELIST lpRecord = NULL;     //表记录指针

const char szFileName[260] = {"c:\\TEMP\\Test.db\0"};

PTABLELIST _Append(void);
PTABLELIST _Insert(void);
PTABLELIST _Delete(void);
int _NewID(void);
void _Free(void);
void _ListHeader(void);
void _ListRecord(PTABLELIST p);
void _List(void);
void _Edit(PTABLELIST p);
void _Input(void);
bool _Open(const char *lpFileName);
bool _Save(const char *lpFileName);
void _Locate(void);

/* 添加记录 */
PTABLELIST _Append(void)
{
    PTABLELIST p = (PTABLELIST)malloc(sizeof(TABLELIST));
    if (p != NULL)
    {
        memset(p, 0, sizeof(TABLELIST));
        p->lpNext  = NULL;
        if (lpTop != NULL)
        {
            lpBottom->lpNext = p;
            p->lpPrior = lpBottom;
            p->stTable.dwID = _NewID();
        }
        else
        {
            p->lpPrior = NULL;
            p->stTable.dwID = 1;
            lpTop = p;
        }
        lpBottom = p;
        lpRecord  = p;
        return p;
    }
    return NULL;
}

/* 插入记录 */
PTABLELIST _Insert(void)
{
    PTABLELIST p = (PTABLELIST)malloc(sizeof(TABLELIST));
    if (p != NULL)
    {
        memset(p, 0, sizeof(TABLELIST));
        if (lpRecord != NULL)
        {
            p->lpPrior = lpRecord;
            p->lpNext  = lpRecord->lpNext;
            p->stTable.dwID = _NewID();
            if (lpRecord != lpBottom)
            {
                lpRecord->lpNext->lpPrior = p;
            }
            else
            {
                lpBottom = p;
            }
            lpRecord->lpNext = p;
        }
        else
        {
            p->lpPrior = NULL;
            p->lpNext  = NULL;
            p->stTable.dwID = 1;
            lpTop = p;
            lpBottom = p;
        }
        lpRecord  = p;
        return p;
    }
    return NULL;
}

int _NewID(void)
{
    int dwID = 0;
    PTABLELIST p;
    p = lpTop;
    while (p != NULL)
    {
        if (p->stTable.dwID > dwID)
        {
            dwID = p->stTable.dwID;
        }
        p = p->lpNext;
    }
    return ++dwID;
}

/* 删除记录 */
PTABLELIST _Delete(void)
{
    if (lpRecord != NULL)
    {
        PTABLELIST p;
        if ((lpRecord != lpTop) && (lpRecord != lpBottom))
        {
            p = lpRecord->lpNext;
            p->lpPrior = lpRecord->lpPrior;
            p->lpPrior->lpNext = p;
        }
        else if ((lpRecord != lpTop) && (lpRecord == lpBottom))
        {
            p = lpRecord->lpPrior;
            p->lpNext = NULL;
            lpBottom  = p;
        }
        else if ((lpRecord == lpTop) && (lpRecord != lpBottom))
        {
            p = lpRecord->lpNext;
            p->lpPrior = NULL;
            lpTop = p;
        }
        else
        {
            p = NULL;
            lpTop = NULL;
            lpBottom = NULL;
        }
        free(lpRecord);
        lpRecord = p;
    }
    return lpRecord;
}

/* 释放所有分配的内存空间 */
void _Free(void)
{
    PTABLELIST p;
    lpRecord = lpTop;
    while (lpRecord != NULL)
    {
        p = lpRecord->lpNext;
        free(lpRecord);
        lpRecord = p;
    }
    lpTop    = NULL;
    lpBottom = NULL;
    lpRecord = NULL;
}

/* 列表头 */
void _ListHeader(void)
{
    printf("\nID         编号       姓名       性别       年龄       级别       评分\n");
}

/* 列表记录 */
void _ListRecord(PTABLELIST p)
{
    if (p != NULL)
    {
        printf("%-10u %-10s %-10s %-10s %-10d %-10s %-10.2lf\n",
               p->stTable.dwID,
               p->stTable.szNumber,
               p->stTable.szName,
               p->stTable.szGender,
               p->stTable.Age,
               p->stTable.szLevel,
               p->stTable.qwScore);
    }
}

/* 列表 */
void _List(void)
{
    _ListHeader();
    char ch;
    lpRecord = lpTop;
    while (lpRecord != NULL)
    {
        _ListRecord(lpRecord);
        lpRecord = lpRecord->lpNext;
    }
    lpRecord = lpBottom;
    _ListHeader();
    _ListRecord(lpRecord);
    do
    {
        printf("选择：1上记录，2下记录，3修改，4插入，5删除，6查询，0退出：");
        ch = ' ';
        while (ch<'0' || ch>'6')
        {
            fflush(stdin);
            ch = getchar();
        }
        switch(ch)
        {
            case '1':
                if (lpRecord != lpTop) lpRecord = lpRecord->lpPrior;
                break;
            case '2':
                if (lpRecord != lpBottom) lpRecord = lpRecord->lpNext;
                break;
            case '3':
                _Edit(lpRecord);
                break;
            case '4':
                _Insert();
                _Edit(lpRecord);
                break;
            case '5':
                _Delete();
                break;
            case '6':
                _Locate();
                break;
            case '0':
                break;
            default :
                break;
        }
        if (ch != '0')
        {
            _ListHeader();
            _ListRecord(lpRecord);
        }
    }
    while (ch != '0');
}

/* 编辑数据 */
void _Edit(PTABLELIST p)
{
    if (p != NULL)
    {
        fflush(stdin);
        printf("请输入员工的信息（ID：%u）\n", p->stTable.dwID);
        printf("编号：");
        scanf("%s", p->stTable.szNumber);
        printf("姓名：");
        scanf("%s", p->stTable.szName);
        printf("性别：");
        scanf("%s", p->stTable.szGender);
        printf("年龄：");
        scanf("%d", &p->stTable.Age);
        printf("级别：");
        scanf("%s", p->stTable.szLevel);
        printf("评分：");
        scanf("%lf",&p->stTable.qwScore);
    }
}

/* 录入数据 */
void _Input(void)
{
    char ch;
    PTABLELIST p;
    do
    {
        p = _Append();
        _Edit(p);
        printf("是否继续录入?(Y/N)：");
        fflush(stdin);
        ch = getchar();
    }
    while (ch!='N' && ch!='n');
}

/* 打开表 */
bool _Open(const char *lpFileName)
{
    if (access(lpFileName, 0) != 0)
    {
        return false;
    }
    FILE *fp;
    if ((fp=fopen(lpFileName, "r")) == NULL)
    {
        return false;
    }
    TABLE stTable;
    PTABLELIST p;
    fread(&stTable, sizeof(TABLE), 1, fp);
    while (feof(fp) == 0)
    {
        p = _Append();
        if (p != NULL)
        {
            memcpy(p, &stTable, sizeof(TABLE));
        }
        fread(&stTable, sizeof(TABLE), 1, fp);
    }
    fclose(fp);
    return true;
}

/* 保存表 */
bool _Save(const char *lpFileName)
{
    FILE *fp;
    if ((fp=fopen(lpFileName, "w")) == NULL)
    {
        return false;
    }
    lpRecord = lpTop;
    while (lpRecord != NULL)
    {
        if (fwrite(lpRecord, sizeof(TABLE), 1, fp) != 1)
        {
            fclose(fp);
            return false;
        }
        lpRecord = lpRecord->lpNext;
    }
    fclose(fp);
    _Free();
    return true;
}

/* 查询数据 */
void _Locate(void)
{
    char szName[30];
    fflush(stdin);
    printf("输入查找的姓名：");
    gets(szName);
    lpRecord = lpTop;
    while (lpRecord != NULL)
    {
        if (strcmp(lpRecord->stTable.szName, szName) == 0)
        {
            break;
        }
        lpRecord = lpRecord->lpNext;
    }
    if (lpRecord == NULL)
    {
        printf("\n无符合条件的记录\n");
        lpRecord = lpBottom;
    }
}

/* 菜单 */
int menu(void)
{
    char ch;
    do
    {
        system("cls");
        printf("\t\t********员工管理系统 **************\n");
        printf("\t\t         1.录入数据                \n");
        printf("\t\t         2.显示数据                \n");
        printf("\t\t         0.退出系统                \n");
        printf("\t\t***********************************\n");
        printf("\t\t选择(0-2):");
        fflush(stdin);
        ch = getchar();
    }
    while (ch<'0' || ch>'2');
    return(ch - '0');
}

int main(void)
{
    _Open(szFileName);
    while (1)
    {
        switch(menu())
        {
            case 1:
                _Input();
                break;
            case 2:
                _List();
                break;
            case 0:
                _Save(szFileName);
                goto _EXIT;
            default :
                break;
        }
    }
_EXIT:
    return 0;
}