Why can't text from a file be inserted into QTextEdit?

Question

Qt

in general, I write like this, but when you run textEdit by the name code is empty, while code.txt definitely has text. what am I doing wrong?

QFile code("code.txt");
      task.open(QIODevice::ReadOnly);
      ui->code->insertPlainText(code.readAll());
   code.close();

Answer 1

QFile code("code.txt");
if (!code.open(QIODevice::ReadOnly | QIODevice::Text)){
    qDebug() << "file doesn't open";
    return ...;
}
ui->code->insertPlainText(code.readAll());
code.close();

Answer 2

Is it displayed in qDebug()? Why is there no check to see if the file was successfully opened?