Question about Constructor

[hakermania]

Actually, I have a C++ program in which I want to make a timer. The timer must be declared and created at the constructor of the program...What does this means?
This is the program:

#include <stdio.h>
#include <time.h>
#include <iostream>
#include <QTimer>
using namespace std;
time_t seconds = time (NULL);

int main ()
{
    QTimer *timer = new QTimer(this);

    connect(timer, SIGNAL(timeout()), this, SLOT(update_time()));

    timer->start(1000);


  return 0;
}

void update_time()
{
    int a=1;
    while(a){
        time_t seconds;
        seconds = time (NULL);}
}

As you understood, I wanna get the time since 1/1/1970 in seconds and to be updated every single second.... Unfortunately, these two:

 QTimer *timer = new QTimer(this);

    connect(timer, SIGNAL(timeout()), this, SLOT(update_time()));

have to be moved into the constructor of the application. How can I do this and what does it mean?
Ask like you'd talk to a newbie plz
Thx!