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

[Baxter]

I am making a project for a school project, and im getting this error

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

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

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from my code

#ifndef __MAIN_H__
#define __MAIN_H__
#include <QMainWindow>
#include <QApplication>
#include <QPushButton>
#include <cstdlib>
#include "ui_menuScreen.h"
 
 
	// connects the code to the UI
	class mathsGame : public :: QDialog, private Ui::mainScreenDLG
	{
		Q_OBJECT
 
	public:
		// makes a new instance of the main dialog
		mainScreenDLG(QDialog *parent = 0);
 
 
 
	}
 
 
#endif

#ifndef __MAIN_H__
#define __MAIN_H__
#include <QMainWindow>
#include <QApplication>
#include <QPushButton>
#include <cstdlib>
#include "ui_menuScreen.h"


	// connects the code to the UI
	class mathsGame : public :: QDialog, private Ui::mainScreenDLG
	{
		Q_OBJECT
	 
	public:
		// makes a new instance of the main dialog
		mainScreenDLG(QDialog *parent = 0);
	
	
	
	}
	

#endif

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[Lykurg]

You must name your constructor mathsGame.

EDIT: and the "::" after public is wrong.

[Baxter]

ahhh yes, thankyou

to avoid confusion, i actually wanted the code to read:

class mainScreen : public :: QDialog, private Ui::mainScreenDLG
	{
		Q_OBJECT
 
	public:
		mainScreen(QDialog *parent = 0);

class mainScreen : public :: QDialog, private Ui::mainScreenDLG
	{
		Q_OBJECT
	 
	public:
		mainScreen(QDialog *parent = 0);

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[Lykurg]

Fine, but still, delete the "::", they do not belong to that place.

[Baxter]

i am now getting these errors for the new code

src/mainScreen.h:12: error: expected class-name before ‘{’ token
src/mainScreen.h:12: error: invalid use of incomplete type ‘struct QDialog’

#ifndef __MAIN_H__
#define __MAIN_H__
#include <QMainWindow>
#include <QApplication>
#include <QPushButton>
#include <cstdlib>
#include "ui_menuScreen.h"
 
	// connects the code to the UI
	class mainScreen : public QDialog, private Ui::mainScreenDLG
	{
		Q_OBJECT
 
	public:
		mainScreen(QDialog *parent = 0);
 
	};
 
#endif

#ifndef __MAIN_H__
#define __MAIN_H__
#include <QMainWindow>
#include <QApplication>
#include <QPushButton>
#include <cstdlib>
#include "ui_menuScreen.h"

	// connects the code to the UI
	class mainScreen : public QDialog, private Ui::mainScreenDLG
	{
		Q_OBJECT
	 
	public:
		mainScreen(QDialog *parent = 0);
	
	};
	
#endif

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[GreenScape]

read carefully:

declaration of ‘mainScreenDLG’ with no type

only constructors and destructors has no return type, you just need to add void (or other return type) before mainScreenDLG:

void mainScreenDLG(QDialog *parent = 0);

void mainScreenDLG(QDialog *parent = 0);

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Fine, but still, delete the "::", they do not belong to that place.

they do! they tell to compiler namespace where QDialog declared. in this case the do nothing beacuse QDialog in global scope.

[GreenScape]

i am now getting these errors for the new code
src/mainScreen.h:12: error: expected class-name before ‘{’ token

Ui::mainScreenDLG - is not correct class name, maybe you missed something?

i am now getting these errors for the new code
src/mainScreen.h:12: error: invalid use of incomplete type ‘struct QDialog’

add #include <QDialog>

[Baxter]

i have been using this tutorial to help me
http://sector.ynet.sk/qt4-tutorial/m...plication.html
the "myqtapp.h" file is what is being referred to by me

[GreenScape]

download QtCreator and be happy!

[ChrisW67]

#ifndef __MAIN_H__
#define __MAIN_H__
#include <QMainWindow>
#include <QApplication>
#include <QPushButton>
#include <cstdlib>
#include "ui_menuScreen.h"  
 
	// connects the code to the UI
	class mainScreen : public QDialog, private Ui::mainScreenDLG 
	{
		Q_OBJECT
 
	public:
		mainScreen(QDialog *parent = 0);
 
	};
 
#endif

#ifndef __MAIN_H__
#define __MAIN_H__
#include <QMainWindow>
#include <QApplication>
#include <QPushButton>
#include <cstdlib>
#include "ui_menuScreen.h"  

	// connects the code to the UI
	class mainScreen : public QDialog, private Ui::mainScreenDLG 
	{
		Q_OBJECT
	 
	public:
		mainScreen(QDialog *parent = 0);
	
	};
	
#endif

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Line 7 seems to include the wrong file, which is probably why Ui::mainScreenDLG is unknown.

[GreenScape]

no, Ui::mainScreenDLG must be in ui_menuScreen.h, look for it.

in fact mainScreenDLG must be the name of the widget class u created in designer.
if mainScreenDLG is not the name of that class replace it with class name

[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)

[ChrisW67]

no, Ui::mainScreenDLG must be in ui_menuScreen.h, look for it.

Greenscape, you seem to be confusing me with the author of the broken program.

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"

Qmake will generate uic commands for the .ui file "mainScreen.ui" to generate a file "ui_mainScreen.h" that contains the definitions for the objects in the design. Your code defining "class mathsGame" (first post) includes a file called "ui_menuScreen.h", which presumably relates to a different Designer form that does not define mainScreenDLG.

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

Probably because it does not know of an object by the name btnCheck which the error reports as "<unresolved overloaded function type>".

[hippo]

Baxter

u try to change class name:mainScreen to myMainScreen or rename other

mainScreen，MainScreen may be retained by QT Create