You opened the file in text mode and you write binary value. The character with code 13 (0xD) is a newline. Open the file in binary mode by removing QIODevice::Text, it should start working.
Qt C++ QDataStream read the number 13
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04-04-2022 - |
Domanda
I want to write a binary file with QDataStream. The problem is with the code below, when I write my_string = "13", I read 0 ; when my_string is not equal to "13" ("12", "14", "20", ...), I read the real value (12, 14, 20, ...). Does anybody know why I have this problem just with the number 13.
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
//open the file to write
QFile file1("test");
if (!file1.open(QIODevice::WriteOnly | QIODevice::Text))
return;
QDataStream stream1(&file1);
QString my_string = "13";
qint8 val8 = my_string.toInt();
stream1 << val8;
file1.close();
//open the file to read
QFile file2("test");
file2.open(QIODevice::ReadOnly | QIODevice::Text);
QDataStream stream2(&file2);
qint8 val2;
stream2>> val2;
QListWidgetItem *item = new QListWidgetItem;
item->setText(QString::number(val2));
ui->listWidget->addItem(item);
file2.close();
}
Soluzione
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