c - C语言更新记录

Question

有人可以帮我处理这段代码吗？当我尝试这段代码时，它根本不起作用。我在使用 C 语言处理文件方面的经验非常少。请帮我解决这个问题

结构如下

struct passenger
{
    char airline[20];
    char name[20];
    int age;
    char gender;
    char clas[10];
    int seatNo;

}e;

这里是插入记录的函数

oid reserve()
{
    int airline, clas;
    printf("\nSelect your flight:");
    printf("\n1. PIA\n2. Shaheen\n3. Air Blue\n\nEnter Choice:");
    scanf("%d", &airline);
    if (airline == 1)
        strcpy(e.airline, "\nPIA");
    else if (airline == 2)
        strcpy(e.airline, "\nShaheen");
    else if (airline == 3)
        strcpy(e.airline, "\nAirBlue");

    printf("\nEnter Name:");
    scanf("%s", &e.name);

    printf("\nEnter Age:");
    scanf("%d", &e.age);

    printf("\nEnter Your Gender (M/F): ");
    e.gender = getche();

    printf("\n\nPress 1 for ECONOMY CLASS and 2 for BUSSINESS CLASS: ");
    scanf("%d", &clas);
    if (clas == 1)
        strcpy(e.clas, "Economy");
    else
        strcpy(e.clas, "Bussiness");
    e.seatNo = rand() % 500;
    printf("\nYour seat num is: %d\n\n", e.seatNo);

    if (airline==1)
        save = fopen("PIA.DAT", "a");
    else if (airline==2)
        save = fopen("Shaheen.DAT", "a");
    else
        save = fopen("AirBlue.DAT", "a");
    fwrite(&e, sizeof( struct passenger), 1, save);
    fclose(save);

    getch();
}

这是为了更新记录

void update()
    int  i = 1, count = 0, clas, record = 0;
    int seat, airline;
    struct passenger se;
    printf("\n\n\nSelect your flight:");
    printf("\n1. PIA\n2. Shaheen\n3. Air Blue\n\nEnter Choice:");
    scanf("%d", &airline);

    if (airline == 1)
        updateR = fopen("PIA.DAT", "r+");
    else if (airline == 2)
        updateR = fopen("Shaheen.DAT", "r+");
    else
        updateR = fopen("AirBlue.DAT", "r+");

    if (updateR == NULL)
    {
        printf("File not found.");
    }
    else
    {
        printf("\nEnter Your Seat No: ");
        scanf("%d", &seat);
        while (!feof(updateR))
        {
            fread(&se, sizeof(struct passenger), 1, updateR);
            if (se.seatNo == seat)
            {
                printf("\nEnter Name:");
                scanf("%s", &e.name);

                printf("\nEnter Age:");
                scanf("%d", &e.age);

                printf("\nEnter Your Gender (M/F): ");
                e.gender = getche();

                printf("\n\nPress 1 for ECONOMY CLASS and 2 for BUSSINESS CLASS: ");
                scanf("%d", &clas);
                if (clas == 1)
                    strcpy(e.clas, "Economy");
                else
                    strcpy(e.clas, "Bussiness");
                fseek(updateR,sizeof(struct passenger)* record, SEEK_END);
                fwrite(&e, sizeof(&e), 1, updateR);
                break;
            }
        }
        fclose(updateR);
    }
    getch();
}

Answer 1

缺少相当多的信息，无法进行全面分析。但乍一看，您是从文件末尾查找。您正在使用SEEK_END。通常您应该使用 SEEK_SET。