error: ISO C++ forbids declaration of ‘mainScreenDLG’ with no type

[Baxter]

the object name is "mainScreenDLG" in the file mainScreen.ui (created in Qt Designer)
i think that it hadnt recognised the mainScreen.ui file until i re-opened it in Designer for some reason. that or i had misnamed it and
but im still getting the "13: error: expected class-name before ‘{’ token"

on a related note, the code from my "mainScreen.cpp" file is experiencing errors

#include <QApplication>
#include <QDataStream>
#include <QtGui>
#include <cstdlib>
#include <ctime>
#include "ui_mainScreen.h"
#include "mainScreen.h"
 
bool selectSum, selectSub, selectMulti, selectDivisi;
 
// code to begin the programme
mainScreen::mainScreen(QDialog *parent)
 
{
		setupUi(this);
 
		// connect the buttons and labels to the code
		connect (btnCheck, SIGNAL( clicked() ), this, SLOT( getPath() ) );
 
};

#include <QApplication>
#include <QDataStream>
#include <QtGui>
#include <cstdlib>
#include <ctime>
#include "ui_mainScreen.h"
#include "mainScreen.h"

bool selectSum, selectSub, selectMulti, selectDivisi;

// code to begin the programme
mainScreen::mainScreen(QDialog *parent)

{
		setupUi(this);
		
		// connect the buttons and labels to the code
		connect (btnCheck, SIGNAL( clicked() ), this, SLOT( getPath() ) );

};

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18: error: no matching function for call to ‘mainScreen::connect(<unresolved overloaded function type>, const char*, mainScreen* const, const char*)’

thankyou for everyone in their help!

EDIT: the new error was because i had tried to link by button to a function that did not exist (getPath)