C 丢失我的文件'；在关闭文件后删除数据

我正试图制作一个保存学校学生记录的文件，除了一个之外，一切都很顺利，那就是在我关闭程序后，数据正在丢失。 有什么问题吗

节目从这里开始：

    #include "stdafx.h"
    #include <stdio.h>
    #include <conio.h>
    #include <iostream>
    #include <string.h>

    using namespace std;

函数原型和main（）

在main（）中询问用户后，此函数创建文件kayit.dat

    void creatfile()
    {
    FILE *fp;
    ogr_t bos_ogr = { 0, 0, 0, 0, 0.0, "", "" };
    if ((fp = fopen("kayit.dat", "wb")) == NULL)
    {
        printf("File was not opened");
    }
    else
    {   //to create a file and initialize it with an empty 100 student record .
        for (int i = 0; i < 100; i++)
        {
            fwrite(&bos_ogr, sizeof(ogr_t), 1, fp);
        }//end for
    }
    system("cls");
    }

此函数使用随机访问添加新记录

    void addrecord(FILE *ptr)
    {
    ogr_t record = { 0, 0, 0, 0, 0.0, "", "" };
    int accnum;
    char c;
    /*Enter a record number and search if is was already input*/
    printf(" Enter a record number for the new student < 1 - 100 > .");
    scanf("%d", &accnum);
    fseek(ptr, (accnum - 1)*sizeof(ogr_t), SEEK_SET);
    fread(&record, sizeof(ogr_t), 1, ptr);
    if (record.kyt_no!=0)
    {
        printf("this record is already full .\n");
        printf("press and key to continue...\n");
        if (c = _getche())
        {
            system("cls");
        }
    }
    else
    {
        printf("%-13s%-13s%-13s%-13s%-13s\n", "Name", "SureName", "StudentNum", "MidtermNote", "FinalNote");
        fscanf(stdin, "%s%s%d%d%d", record.ad, record.soyad, &record.ogrno, &record.vize, &record.final);
        record.kyt_no = accnum;
        fseek(ptr, (record.kyt_no - 1)*sizeof(ogr_t), SEEK_SET);
        fwrite(&record, sizeof(ogr_t), 1, ptr);
    }
    system("cls");
    }

根据用户选择的条件搜索特定记录

    void updaterecord(FILE *ptr)
    {
    ogr_t record1 = { 0, 0, 0, 0, 0.0, "", "" };
    int accnum;
    char c;
    printf(" Enter the student's record number that you want to update  < 1 - 100 > .");
    scanf("%d", &accnum);
    fseek(ptr, (accnum - 1)*sizeof(ogr_t), SEEK_SET);
    fread(&record1, sizeof(ogr_t), 1, ptr);
    if (record1.kyt_no == 0)
    {
        printf("This record is empty\n");
        printf("press and key to continue...\n");
        if (c= _getche())
        {
            system("cls");
        }
    }
    else
    {
        printf("Enter the new informations\n");
        printf("%-13s%-13s%-13s%-13s%-13s\n", "Name", "SureName", "StudentNum", "MidtermNote", "FinalNote");
        fscanf(stdin, "%s%s%d%d%d", record1.ad, record1.soyad, &record1.ogrno, &record1.vize, &record1.final);
        record1.kyt_no = accnum;
        fseek(ptr, (record1.kyt_no - 1)*sizeof(ogr_t), SEEK_SET);
        fwrite(&record1, sizeof(ogr_t), 1, ptr);
        system("cls");
    }

    }

void searchrecord(FILE *ptr)
{
    int request;
    int recnum;
    char name[20];
    ogr_t ogr;
    int mark;
    printf("Enter by what criteria do you want to search .\n\n"
        "1- By record num.\n"
        "2- By Name.\n"
        "3- By Grade.\n");
    scanf("%d", &request);
    system("cls");
    switch (request)
    {
    case 1:
        printf("Enter the record number .");
        scanf("%d", &recnum);
        fseek(ptr, (recnum - 1)*sizeof(ogr_t), SEEK_SET);
        fread(&ogr, sizeof(ogr_t), 1, ptr);
        printf("%-13s%-13s%-13s%-13s%-13s%-13s\n", "RecordNumber", "Name", "Surename", "StudentNum", "MidtermNote", "FinalNote");
        printf("%-13d%-13s%-13s%-13d%-13d%-13d\n", ogr.kyt_no, ogr.ad, ogr.soyad, ogr.ogrno, ogr.vize, ogr.final);
        break;
    case 2:
        printf("Enter the name of the student .\n ");
        scanf("%s",name);
        rewind(ptr);
        fread(&ogr, sizeof(ogr_t), 1, ptr);
        while (!feof(ptr))
        {
            if (strcmp(name, ogr.ad) == 0)
            {
                printf("%-13s%-13s%-13s%-13s%-13s%-13s\n", "RecordNumber", "Name", "Surename", "StudentNum", "MidtermNote", "FinalNote");
                printf("%-13d%-13s%-13s%-13d%-13d%-13d\n", ogr.kyt_no, ogr.ad, ogr.soyad, ogr.ogrno, ogr.vize, ogr.final);
            }
            fread(&ogr, sizeof(ogr_t), 1, ptr);
        }
        break;
    case 3:
        printf("Enter the Mark the you want to search for.\n ");
        scanf("%d",&mark);
        printf("The student that had higher than the mark that you've enterd are \n\n");
        rewind(ptr);
        fread(&ogr, sizeof(ogr_t), 1, ptr);
        while (!feof(ptr))
        {
            if (ogr.kyt_no!=0)
            {
                ogr.ort = ((ogr.final) + (ogr.vize)) / 2;
                if ((ogr.ort)>=mark)//print the records that have a higher averager than the mark.
                {
                    printf("%-13s%-13s%-13s%-13s%-13s%-13s\n", "RecordNumber", "Name", "Surename", "StudentNum", "MidtermNote", "FinalNote");
                    printf("%-13d%-13s%-13s%-13d%-13d%-13d\n", ogr.kyt_no, ogr.ad, ogr.soyad, ogr.ogrno, ogr.vize, ogr.final);
                }
            }
            fread(&ogr, sizeof(ogr_t), 1, ptr);
        }
        break;
    default:printf("Undefined choice.\n");
        break;
    }
}

---

节目结束了

在这种情况下，我要做的第一件事就是

确保每个fopen（）调用都有一个fclose（）调用

因此，在createfile（）中，您可以在写入模式下打开文件，而不关闭该文件。。用rb+模式再次打开该文件，这样会导致问题

您应该在编写之后关闭createfile（）中的文件，这样您的代码就会像

void creatfile()
{
FILE *fp;
ogr_t bos_ogr = { 0, 0, 0, 0, 0.0, "", "" };
if ((fp = fopen("kayit.dat", "wb")) == NULL)
{
    printf("File was not opened");
}
else
{   //to create a file and initialize it with an empty 100 student record .
    for (int i = 0; i < 100; i++)
    {
        fwrite(&bos_ogr, sizeof(ogr_t), 1, fp);
    }//end for

    //Lets close the file         
    fclose(fp);
}
system("cls");
}

void创建文件（）
{
文件*fp；
ogr_t bos_ogr={0,0,0,0,0.0，“，”}；
if（（fp=fopen（“kayit.dat”，“wb”））==NULL）
{
printf（“文件未打开”）；
}
其他的
{//创建一个文件并用一个空的100学生记录初始化它。
对于（int i=0；i<100；i++）
{
fwrite&bos_ogr，sizeof（ogr_t），1，fp；
}//结束
//让我们关闭文件
fclose（fp）；
}
系统（“cls”）；
}

（1）请使用适当的缩进设置代码格式。这真的很难读。（2） 这是很多代码。请编辑您的帖子，欢迎来到stackoverflow。这对于获得有用的答案来说是太多的代码了，而且您甚至没有在一个地方给出一个可运行的程序。但是我注意到

createfile

将清空文件的内容（如果存在）。这是故意的吗？在

createfile

中，您在完成写入文件后忘记关闭文件。@alexis在main（）函数中，我询问用户是创建文件还是继续创建文件（如果已经创建），因此文件将仅根据用户的要求创建，但如果您选择以“wb”的形式打开文件所有信息都将丢失问题是我正在运行程序，我选择在第一次运行时创建文件并输入一些记录，在第二次运行时，我选择不创建新文件，因为它已经创建，而是我想继续读取记录，但即使我不再创建文件，它也会丢失！你是天才@PaulR问题解决了多亏了一个笨蛋我读了100遍代码我都没注意到。

    void updaterecord(FILE *ptr)
    {
    ogr_t record1 = { 0, 0, 0, 0, 0.0, "", "" };
    int accnum;
    char c;
    printf(" Enter the student's record number that you want to update  < 1 - 100 > .");
    scanf("%d", &accnum);
    fseek(ptr, (accnum - 1)*sizeof(ogr_t), SEEK_SET);
    fread(&record1, sizeof(ogr_t), 1, ptr);
    if (record1.kyt_no == 0)
    {
        printf("This record is empty\n");
        printf("press and key to continue...\n");
        if (c= _getche())
        {
            system("cls");
        }
    }
    else
    {
        printf("Enter the new informations\n");
        printf("%-13s%-13s%-13s%-13s%-13s\n", "Name", "SureName", "StudentNum", "MidtermNote", "FinalNote");
        fscanf(stdin, "%s%s%d%d%d", record1.ad, record1.soyad, &record1.ogrno, &record1.vize, &record1.final);
        record1.kyt_no = accnum;
        fseek(ptr, (record1.kyt_no - 1)*sizeof(ogr_t), SEEK_SET);
        fwrite(&record1, sizeof(ogr_t), 1, ptr);
        system("cls");
    }

    }

    void deleterecord(FILE *ptr)
    {
    ogr_t bos_ogr = { 0, 0, 0, 0, 0.0, "", "" };
    ogr_t record2;
    int accnum;
    char c;
        printf("Enter the record for the student that you want delete < 1 - 100 >\n");
        fscanf(stdin, "%d", &accnum);
        fseek(ptr, (accnum - 1)*sizeof(ogr_t), SEEK_SET);
        fread(&record2, sizeof(ogr_t), 1, ptr);
        if (record2.kyt_no == 0)
        {
            printf("The record is already empty .\n");
            printf("press and key to continue...\n");
            if (c = _getche())
            {
                system("cls");
            }
        }
        else
        {
            fseek(ptr, (accnum - 1)*sizeof(ogr_t), SEEK_SET);
            fwrite(&bos_ogr, sizeof(ogr_t), 1, ptr);
            system("cls");
        }
    }

void listrecords(FILE *ptr)
{
    ogr_t record_prnt;
    char c;
    printf("%-13s%-13s%-13s%-13s%-13s%-13s\n", "RecordNo", "Name", "Surname", "StudentNum", "MidtermNote", "FinalNote");
    rewind(ptr);
    fread(&record_prnt, sizeof(ogr_t), 1, ptr);
    while (!feof(ptr))
    {
        if (record_prnt.kyt_no == 0)
        {
            record_prnt = { 0, 0, 0, 0, 0.0, "", "" };
        }
        else
        {
            printf("%-13d%-13s%-13s%-13d%-13d%-13d\n",
                record_prnt.kyt_no, record_prnt.ad,
                record_prnt.soyad, record_prnt.ogrno,
                record_prnt.vize, record_prnt.final);
        }
        fread(&record_prnt, sizeof(ogr_t), 1, ptr);
    }
    printf("press any key to contiue ...\n");
    if (c = _getche())
    {
        system("cls");
    }
}

void searchrecord(FILE *ptr)
{
    int request;
    int recnum;
    char name[20];
    ogr_t ogr;
    int mark;
    printf("Enter by what criteria do you want to search .\n\n"
        "1- By record num.\n"
        "2- By Name.\n"
        "3- By Grade.\n");
    scanf("%d", &request);
    system("cls");
    switch (request)
    {
    case 1:
        printf("Enter the record number .");
        scanf("%d", &recnum);
        fseek(ptr, (recnum - 1)*sizeof(ogr_t), SEEK_SET);
        fread(&ogr, sizeof(ogr_t), 1, ptr);
        printf("%-13s%-13s%-13s%-13s%-13s%-13s\n", "RecordNumber", "Name", "Surename", "StudentNum", "MidtermNote", "FinalNote");
        printf("%-13d%-13s%-13s%-13d%-13d%-13d\n", ogr.kyt_no, ogr.ad, ogr.soyad, ogr.ogrno, ogr.vize, ogr.final);
        break;
    case 2:
        printf("Enter the name of the student .\n ");
        scanf("%s",name);
        rewind(ptr);
        fread(&ogr, sizeof(ogr_t), 1, ptr);
        while (!feof(ptr))
        {
            if (strcmp(name, ogr.ad) == 0)
            {
                printf("%-13s%-13s%-13s%-13s%-13s%-13s\n", "RecordNumber", "Name", "Surename", "StudentNum", "MidtermNote", "FinalNote");
                printf("%-13d%-13s%-13s%-13d%-13d%-13d\n", ogr.kyt_no, ogr.ad, ogr.soyad, ogr.ogrno, ogr.vize, ogr.final);
            }
            fread(&ogr, sizeof(ogr_t), 1, ptr);
        }
        break;
    case 3:
        printf("Enter the Mark the you want to search for.\n ");
        scanf("%d",&mark);
        printf("The student that had higher than the mark that you've enterd are \n\n");
        rewind(ptr);
        fread(&ogr, sizeof(ogr_t), 1, ptr);
        while (!feof(ptr))
        {
            if (ogr.kyt_no!=0)
            {
                ogr.ort = ((ogr.final) + (ogr.vize)) / 2;
                if ((ogr.ort)>=mark)//print the records that have a higher averager than the mark.
                {
                    printf("%-13s%-13s%-13s%-13s%-13s%-13s\n", "RecordNumber", "Name", "Surename", "StudentNum", "MidtermNote", "FinalNote");
                    printf("%-13d%-13s%-13s%-13d%-13d%-13d\n", ogr.kyt_no, ogr.ad, ogr.soyad, ogr.ogrno, ogr.vize, ogr.final);
                }
            }
            fread(&ogr, sizeof(ogr_t), 1, ptr);
        }
        break;
    default:printf("Undefined choice.\n");
        break;
    }
}

void creatfile()
{
FILE *fp;
ogr_t bos_ogr = { 0, 0, 0, 0, 0.0, "", "" };
if ((fp = fopen("kayit.dat", "wb")) == NULL)
{
    printf("File was not opened");
}
else
{   //to create a file and initialize it with an empty 100 student record .
    for (int i = 0; i < 100; i++)
    {
        fwrite(&bos_ogr, sizeof(ogr_t), 1, fp);
    }//end for

    //Lets close the file         
    fclose(fp);
}
system("cls");
}