The qlineedit control allows only integer/floating point numbers.

In MFC programming, we can setAttribute of the input boxAllows users to enter only numbers.

Input box in QT (Qlineedit) Can be boundQintvalidator/Qdoublevalidator/QregexpvalidatorObject To control user input.

***

Qintvalidator-- Only allow the user to enter an integer

Qdoublevalidator-- Only allow users to enter floating point numbers

Qregexpvalidator-- Only allow users to enter the style defined according to the Regular Expression

**

--- The following is an example that only allows the user to input an integer of [-50, 50 ---

QLineEdit* aEdit = new QLineEdit;QIntValidator* aIntValidator = new QIntValidator;aIntValidator->setRange(-50, 50);aEdit->setValidator(aIntValidator);

Qdoublevalidator is similar to qregexpvalidator. For qregexpvalidator, the key is to construct a regular expression that meets your own conditions.