What does it mean?

[anafor2004]

When we define a class in a header file, i write down this code "" Ui::Dialog ui; ""
what does it mean?
If we have Two form first one is MainWindow the second one is Dialog window, these forms all classes contains these code why?

class MainWindow : public QMainWindow, public Ui::MainWindow
{
    Q_OBJECT
public:
 
    int i;
    QTranslator translator;
    //Dialog::Dialog *a=new Dialog();
	 MainWindow(QWidget *parent = 0);
	~MainWindow();
 
 
private:	
    Ui::MainWindow 		ui;
 
 
    void languageChange(int);
 
protected:
		void changeEvent(QEvent* event);
		void keyPressEvent(QKeyEvent *e);
public slots:
	void english();
	void turkce();
	void deutsch();
	void reset();
	void sayfa();
 
 
};
 
class Dialog : public QDialog , public Ui::Dialog 
{
    Q_OBJECT
public:
	Dialog(QWidget *parent = 0);
 
private:	
    Ui::Dialog		ui;
 
   public slots:
		void gizle();
 };

class MainWindow : public QMainWindow, public Ui::MainWindow
{
    Q_OBJECT
public:
	
    int i;
    QTranslator translator;
    //Dialog::Dialog *a=new Dialog();
	 MainWindow(QWidget *parent = 0);
	~MainWindow();
	

private:	
    Ui::MainWindow 		ui;
    
    
    void languageChange(int);
 
protected:
		void changeEvent(QEvent* event);
		void keyPressEvent(QKeyEvent *e);
public slots:
	void english();
	void turkce();
	void deutsch();
	void reset();
	void sayfa();
 
    
};

class Dialog : public QDialog , public Ui::Dialog 
{
    Q_OBJECT
public:
	Dialog(QWidget *parent = 0);
	
private:	
    Ui::Dialog		ui;

   public slots:
		void gizle();
 };

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thanks

[high_flyer]

When we define a class in a header file, i write down this code "" Ui:ialog ui; ""
what does it mean?

It means the same as

int var;

int var;

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But in this case the type of the variable 'ui' is of type 'MainWindow' which is under the scope or namespace 'Ui'.

In this case, these are variables generated automatically by the uic (the ui compiler) out of the form you destined with designer (and saved as a *.ui file).

f we have Two form first one is MainWindow the second one is Dialog window, these forms all classes contains these code why?

Here is why.

[anafor2004]

Thanks for your reply.

[jpn]

You're mixing Single Inheritance and Multiple Inheritance approaches. Highly recommended reading: Qt Designer Manual- Using a Component in Your Application.