return key doesn’t work when i use regex in QT C++

Hey guys I’m trying to use regex on line edit in QT but when I use my regex one function that do something when I enter the return key on keyboard doesn’t work any more!

This is my regex on line edit:

QRegularExpression r("[0-9\.\+\-\=\/\*n]{100}");
ui->lineEdit->setValidator(new QRegularExpressionValidator (r,this));

And this is my function test:

void MainWindow::on_lineEdit_returnPressed()

I also try my regex without “n” but doesn’t change any thing. When I comment the regex my function works correctly.

So any solution?


Your regex needs to support a pattern of length one, thus, {100} quantifier should be replaced with {1,100} or even {0,100}.

Besides, you may also add r (carriage return) char to the character set, and remove unnecessary escapes:

QRegularExpression r("^[0-9.+=/*nr-]{1,100}$");

I added ^ and $ anchors to make sure the regex only matches the whole string (here, line).