Creating a class variable instance without initializing it: unknown override specifier - c++

Question

I am trying to create an object of my class ArduinoControl as a class variable in my QT QMainWindow class.
I have included the ArduinoControl header file in the Main Window header file.
I want to declarate the Arduino object, without initializing it, this will be done in the constructor of the MainWindow object, so that all functions can access the Arduino Object.
This is my QMainWindowClass:
#pragma once
#include <QtWidgets/QMainWindow>
#include "ui_laserbasictestfunctions.h"
#include <QTextEdit>
#include <QLineEdit>
#include <QLabel>
#include "PrintBlock.h"
#include <stdio.h>
#include "ArduinoCommunication.h"
#include <QThread>
#include <QtTest/QtTest>
class LaserBasicTestFunctions : public QMainWindow
{
Q_OBJECT
public:
LaserBasicTestFunctions(QWidget *parent = Q_NULLPTR);
void checkActivity();
private:
Ui::LaserBasicTestFunctionsClass ui;
int programNumber;
bool ok;
bool rotate;
char portName[11];
ArduinoCommunication tableControl;
private slots:
//Tab#1 Laser Test Functions
void on_coordinateSystemButton_clicked();
void on_rectangleButton_clicked();
void on_pointButton_clicked();
void on_stopLaserButton_clicked();
void on_startButton_clicked();
//Tab#2 Print Block Functions
void on_stopLaserButton_2_clicked();
void on_startPrintBlockButton_clicked();
//Tab#3 Arduino Functions
void on_arduinoLEDButton_clicked();
}
This is the Arduino Communication header:
#pragma once
#include <iostream>
#include "SerialPort.h"
#include "ui_laserbasictestfunctions.h"
#include "laserbasictestfunctions.h"
#include <stdio.h>
#include <string.h>
#include <string>
class ArduinoCommunication {
private:
Ui::LaserBasicTestFunctionsClass& ui_;
int pin_piston1_;
int pin_suction_cup_;
int pin_led_;
char incomingData_[MAX_DATA_LENGTH];
SerialPort* arduino_;
char* portname_;
void connect_to();
void receiveData();
public:
ArduinoCommunication(char portname[], int pin_piston1, int pin_suction_cup, int pin_led, Ui::LaserBasicTestFunctionsClass& ui);
ArduinoCommunication();
void set_pin(int pin, bool high);
void actuate_pistons(bool actuate);
void actuate_suction_cup(bool actuate);
void actuate_led(bool actuate);
};
I get the following error messages:
1. 'ArduinoCommunication' no appropriate default constructor available
2. 'tableControl': unknown override specifier
3. missing type specifier - int assumed
I tried creating the ArduinoCommunication object in the constructor of QMainWindow, but then I was not able to access it via the private slot functions.
Any help is welcome!