Converting data types and making a small calculator

The most commonly used widget for accepting one-line data is the Line Edit widget, and the default data type in a Line Edit widget is string. In order to do any computation on two integer values, you need to convert the string data entered in the Line Edit widget to the integer data type and then convert the result of computation, which will be a numeric data type, back to string type before being displaying through a Label widget. This recipe does exactly that.

How to do it...

To understand how data is accepted by the user and how type casting is done, let's create an application based on the Dialog without Buttons template by performing the following steps:

1. Add three QLabel, two QLineEdit, and one QPushButton widget to the form by dragging and dropping three Label, two Line Edit, and four Push Button widgets on the form.
2. Set the text property of the two Label widgets to Enter First Number and Enter Second Number.
3. Set the objectName property...