第二次打开文件无法写入。。。

[zhangwh1991]

const Book mark = {"0","0","0","0","0","0"}; //empty record
const char* bookDat = "D:\\book.dat";
bool flag = true;

void adminWidget::Initial()
{

    QMessageBox box;
    box.setWindowTitle("Warning");
    box.setIcon(QMessageBox::Warning);
    box.setText("If data file exists , it will delete original data.\nContinue ?");
    box.setStandardButtons(QMessageBox::Yes | QMessageBox::No);
    if(box.exec() == QMessageBox::Yes)
    {
        ofstream bdat(bookDat,ios::out | ios::binary);
        if(!bdat)
        {
            QMessageBox::warning(this,tr("Warning"),tr("The file does not exist!"),QMessageBox::Yes);
            flag = false;
            return;
        }
        bdat.seekp(0, ios::beg);
        bdat.write((char*) & mark, sizeof(Book));
        bdat.close();
    }
}
void adminWidget::Append()
{
    Book book;
    fstream bdat(bookDat,ios::in | ios::out | ios::binary);
    if(!bdat)
    {
        QMessageBox::warning(this,tr("Warning"),tr("The file does not exist!"),QMessageBox::Yes);
        return;
    }
    bdat.seekg(0,ios::beg);
    do
    {
     bdat.read((char*)&book,sizeof(Book));
    }while(!endMark(book));
     bdat.seekp(-long(sizeof(Book)),ios::cur);
     book.number = ui->bookNum->text();
     book.bookName = ui->bookName->text();
     book.Author = ui->Author->text();
     book.publish_company = ui->publishingCom->text();
     book.quantity = ui->bookQuantity->text();
     book.price = ui->price->text();
     bdat.write((char*)&book,sizeof(Book));
     bdat.write((char* )&mark,sizeof(Book));
     bdat.close();
}

先调用Initial()初始化文件，可正常调用Append()写文件。。第二次开始就不必调用Initial(),直接调用Append()。。。出错了。。为什么？哪里有问题？望指教！

[就想叫yoko]

出的什么错呢
会不会是bookDat字符串改变了

[bdmh]

那跟踪啊，很可能出在while循环，因为到了末尾时，并不是立即就知道已经到末尾了，是需要再次读取一下，才知道

[wfq0987]

Initial()和Append（）之间没有哦什么因果联系啊

[luciferisnotsatan]

第二次打开进
QMessageBox::warning(this,tr("Warning"),tr("The file does not exist!"),QMessageBox::Yes);
这句么？？