Connect, сигналы слоты восстановление связи

#include <QApplication>
#include <QLabel>
#include <QPushButton>
#include "counter.h"
int main(int argc, char *argv[])
{
    bool Check = true;
    QApplication a(argc, argv);
    QLabel lbl("0");
    lbl.setMinimumSize(200,100);
    QPushButton cmd("ADD");
    cmd.setMinimumSize(200,100);
    QPushButton cmd2("DISCONNECT/CONNECT");
    cmd2.setMinimumSize(200,100);
    Counter counter;
    lbl.show();
    cmd.show();
    cmd2.show();
 
    QObject::connect(&cmd, SIGNAL(clicked()),&counter, SLOT(slotInc()) ); //Add
 
    if(Check == true)
    {
        Check = false;
        QObject::connect(&cmd2, SIGNAL(clicked()),&counter, SLOT(disconnector()) );//Con DisCon
 
    }
    else
    {
        Check = true;
        QObject::connect(&cmd2, SIGNAL(clicked()),&counter, SLOT(connector()) );//Con DisCon
 
    }
 
    QObject::connect(&counter, SIGNAL(counterChanged(int)), &lbl, SLOT(setNum(int)) ); //Add
 
    QObject::connect(&counter, SIGNAL(goodbye()), &a, SLOT(quit()) );
    return a.exec();
}

#ifndef counter_h
#define counter_h
#include <QObject>
class Counter : public QObject
{
    Q_OBJECT
private:
    int Value;
public:
    Counter(QObject *parent=0);
public slots:
    void slotInc();
    void disconnector();
    void connector();
signals:
    void goodbye ();
    void counterChanged(int);
};
#endif // COUNTER_H

#include "counter.h"
Counter::Counter (QObject *parent) : QObject(parent), Value(0) { }
 
void Counter::slotInc()
{
    emit counterChanged(++Value);
    if (Value == 15) { emit goodbye(); }
}
 
void Counter::disconnector()
{
    this->disconnect();
 }
 
void Counter::connector()
{
    this->connect(); //Ошибка
}

private:
    int Value;
    bool state;     // <------ flag

void Counter::slotInc() {
    if (state) {
        emit counterChanged(++Value);
        if (Value == 15) { emit goodbye(); }
    }
}
 
void Counter::disconnector() {
    state = !state;
}