General

What does QString mean?

By Angel Hume

What does QString mean?

QString stores unicode strings. By definition, since QString stores unicode, a QString knows what characters it’s contents represent. This is in contrast to a C-style string (char*) that has no knowledge of encoding by itself. Internally, QString stores the string using the UTF-16 encoding.

How do I assign QString to QString?

There a couple of ways to do this, the easiest is to just do: QString s = “0”; If you are trying to assign an int variable to a string you can do: int i = 0; QString s(“%1”).

How do you make QString?

One way to initialize a QString is simply to pass a const char * to its constructor. For example, the following code creates a QString of size 5 containing the data “Hello”: QString str = “Hello”; QString converts the const char * data into Unicode using the fromAscii() function.

How do you convert QString to double in Qt?

QString to double convertion problem

  1. lineEdit->setText(“123456789”);
  2. QVariant val = lineEdit->text(). toDouble();
  3. qDebug() << val;
  4. .
  5. .
  6. .
  7. lineEdit2->setText(val. toString());

How do you convert QString to QByteArray in Qt?

convert QString to QByteArray

  1. QString memo_text=textEdit. toPlainText();
  2. qDebug()<
  3. QByteArray textTemp(memo_text. toUtf8() ,1000);
  4. qDebug()<
  5. strcpy(memo_info->text , textTemp.
  6. qDebug()<

Where can I find qDebug output?

There is a tab named 3 – Application output at the very bottom of the Qt Creator. Clicking that window will show you the Application output window at the bottom of Qt Creator. That particular window will display the qDebug() messages as soon as they get called while the application is still running.

Is QString null terminated?

The QChar array of the QString (as returned by unicode()) is not terminated by a null. A QString that has not been assigned to anything is null, i.e. both the length and data pointer is 0.

How do I add to QString?

Try using “\”” . I would do it like: QString str = QString(“”). arg(myVar); . This will work even if myVar is an integer.

What is QDebug in Qt?

The QDebug class provides an output stream for debugging information. QDebug is used whenever the developer needs to write out debugging or tracing information to a device, file, string or console.

How do I set QString to null?

To create a null QString just default initialize it: QString phoneNumber; // or if you already have a QString variable and want to ‘clear’ it: phoneNumber = QString(); Note that QString::number(0) is decidedly not null – it creates a QString with the value “0” .

How to print a QString with qdebug?

According to Qt Core 5.6 documentation you should use qUtf8Printable () from header to print QString with qDebug. You should do as follows: Show activity on this post. Option 1: Use qDebug’s default mode of a C-string format and variable argument list (like printf):

Is it possible to use swprintf with QString?

QString is UTF-16 internally so there’s no point in doing it via std::swprintf. Format string in QString::asprintf is expected to be UTF-8 so it can hold whatever UTF-16 can. If you have arguments that are UTF-16 strings then these are also supported directly via %lc and %ls.

What is the UTF-16 of a QString?

QString is UTF-16 internally so there’s no point in doing it via std::swprintf. Format string in QString::asprintf is expected to be UTF-8 so it can hold whatever UTF-16 can.

Is it possible to use Unicode in a QString?

You don’t need std to use Unicode (and by Unicode I mean UTF-16, just to be clear, because there’s more then one type of Unicode). QString is UTF-16 internally so there’s no point in doing it via std::swprintf. Format string in QString::asprintf is expected to be UTF-8 so it can hold whatever UTF-16 can.