Unwanted character in CSV file when serializing from QTableWidget

I am trying to read data from a QTableWidget, and save them in a CSV file.

The values saved in the file are correct, but for the first column in every row there is an unwanted character in the beginning.

Here is my code:

void Task::on_button_Export_clicked()
{
    QString fileName = QFileDialog::getSaveFileName(this,tr("Export Task List"), "",tr("CSV Files (*.csv)"));
    if (fileName.isEmpty())
            return;
    else
    {
        QFile file(fileName);
        if (!file.open(QIODevice::WriteOnly))
        {
            QMessageBox::information(this, tr("Unable to open file"),
            file.errorString());
            return;
        }
        QDataStream out(&file);
        out.setVersion(QDataStream::Qt_5_4);
        int rowCount = ui->tableWidget->rowCount();
        int colCount = ui->tableWidget->columnCount();
        for (int i = 0; i < rowCount; i++)
         {
            QString str(QString::null);

           /* if (i > 0)
            {
               str = "\n";
            }*/

            for (int j = 0; j < colCount; j++)
            {
               if (j > 0)
               {
                  str += ",";
               }
               QTableWidgetItem* item = ui->tableWidget->item(i,j);
               str += item->data(Qt::DisplayRole).toString();
            }
            str += "\n";
            out << str;
         }
    }
}

The saved file looks like this:

ÎDPC Task
ÞMain Task
ÌWorkLoop
ÐWorkLoop
ÌIST0
ÊIST1
ÆIST2

I am using Qt 5.4.0.

Any help here would be greatly appreciated.

Your else in the beginning is useless if you use return to ends execution of the function (you didn't use else in the second test).

If you need to write text, you should use a QTextStream instead of a QDataStream which is designed to read/write binary data.

Why using a temporary QString in you loops? You have a stream, use it:

void Task::on_button_Export_clicked() {
    QString fileName = QFileDialog::getSaveFileName(
        this,tr("Export Task List"), "",tr("CSV Files (*.csv)")
    );
    if (fileName.isEmpty()) {
        return;
    }

    QFile file(fileName);
    if (!file.open(QIODevice::WriteOnly)) {
        QMessageBox::information(this, tr("Unable to open file"),
        file.errorString());
        return;
    }

    QTextStream out(&file);
    int rowCount = ui->tableWidget->rowCount();
    int colCount = ui->tableWidget->columnCount();

    for (int i = 0; i < rowCount; i++) {
        /* if (i > 0) {
            out << "\n";
        }*/
        for (int j = 0; j < colCount; j++) {
            if (j > 0) {
                out << ",";
            }
            QTableWidgetItem* item = ui->tableWidget->item(i,j);
            out << item->data(Qt::DisplayRole).toString();
        }
        out << "\n";
    }
}