QT validater

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QRegExpValidator>
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    //ui->lineEdit->setInputMask("000.000.000.000;");


    QRegExp exp("((2[0-4]\\d|25[0-5]|[01]?\\d\\d?)\\.){3}(2[0-4]\\d|25[0-5]|[01]?\\d\\d?)$");
    QRegExpValidator *ipVal  = new QRegExpValidator(exp);
    ui->lineEdit->setValidator(ipVal);
}

MainWindow::~MainWindow()
{
    delete ui;
}