Temporizador en Qt

temporizador-en-qt.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QTimer>
#include <QDateTime>

int cont=0;

void MainWindow::fTimer(){
              ui->lcdNumber->display(cont++);
              ui->label_2->setText(QDateTime::currentDateTime().toString());
}

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    ui->lcdNumber->setFrameStyle(QFrame::NoFrame);

    QTimer *cronometro = new QTimer(this);
    connect(cronometro, SIGNAL(timeout()),this,SLOT(fTimer()));
    cronometro->start(10);
}

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