Need help with basic C++

[arturs]

I need help again.

I created a class "Count" there are some methods,argument etc.

In MainWidnow I created table of Objects
"
Count number[15];

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);

}

From MainWidnow object I created new object preview

"
void MainWindow:n_actionActionpreview_triggered()
{

preview = new Preview(this);
preview->setModal(true);
preview->get_path(&filename);
preview->exec();

}"

I would like to see "number object" which I created in MainWindow from "preview". How to do it ?


I hope I described my problem clearly.

[ChrisW67]

Please use [code]...[/code] tags around code.

Where is the numbers[] array declared?
How have you tried to access it?
How has that failed?

Have you considered explicitly passing the number array to the preview object ?

[arturs]

I have the following Count class

[U]count.h[/U]
 
class Count
{
 
private:
 
bool table[19][8];
 
QString line
 
 public:
 
   int start_line,end_line,alarm_lines; start_line,end_line,alarm_lines;
};

[U]count.h[/U]

class Count
{

private:

bool table[19][8];

QString line

 public:
   
   int start_line,end_line,alarm_lines; start_line,end_line,alarm_lines;
};

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in MainWindow.cpp

I create new objects "Count number [15]" this way

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "count.h"
 
Count number[15];
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
 
    ui->setupUi(this);
 
}

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "count.h"

Count number[15];

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{

    ui->setupUi(this);

}

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and in one of methods MainWindows I create new Object

void MainWindow::on_actionActionpreview_triggered()
{
 
preview = new Preview(this);
preview->setModal(true);
preview->exec();
 
 
}

void MainWindow::on_actionActionpreview_triggered()
{

preview = new Preview(this);
preview->setModal(true);
preview->exec();


}

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In the method void Preview:n_pushButton_clicked() I would like to change start_line in object number[0]

#include "preview.h"
#include "ui_preview.h"
#include <QDebug>
#include "mainwindow.h"
 
Preview::Preview(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::Preview)
{
 
    ui->setupUi(this);
 
 
}
 
 
void Preview::on_pushButton_clicked()
{
number[0].start_line = 5;
}

#include "preview.h"
#include "ui_preview.h"
#include <QDebug>
#include "mainwindow.h"

Preview::Preview(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::Preview)
{

    ui->setupUi(this);


}


void Preview::on_pushButton_clicked()
{
number[0].start_line = 5;
}

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but during compilation I have the following error :" 'alarm' was not declared in this scope"


What are the possibilities to change the start line for the number [0] ?

Regards
Artur

[ChrisW67]

The error message has nothing to do with your question.
Where is the code that tries to use a variable/name "alarm"? The error message from the compiler will have the file and line number.

[jefftee]

I create new objects "Count number [15]" this way

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "count.h"
 
Count number[15];
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
 
    ui->setupUi(this);
 
}

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "count.h"

Count number[15];

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{

    ui->setupUi(this);

}

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Since you are allocating an array of your Count class outside of any class definition, you're are creating a global variable, which you should generally try to avoid doing. You should move that to make your Count array a member variable in your MainWindow class IMHO.

[arturs]

Sorry I made a mistake. I mean number not alarm and I would like to use it in the code

#include "preview.h"
    #include "ui_preview.h"
    #include <QDebug>
    #include "mainwindow.h"
 
    Preview::Preview(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::Preview)
    {
 
    ui->setupUi(this);
 
 
    }
 
 
    void Preview::on_pushButton_clicked()
    {
    number[0].start_line = 5;
    }

#include "preview.h"
    #include "ui_preview.h"
    #include <QDebug>
    #include "mainwindow.h"
     
    Preview::Preview(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::Preview)
    {
     
    ui->setupUi(this);
     
     
    }
     
     
    void Preview::on_pushButton_clicked()
    {
    number[0].start_line = 5;
    }

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[anda_skoa]

The easiest way of having two classes share access to data is to pass a reference or pointer to that variable from the the object that created the variable to the other object.
In your case passing a reference or point to "number" as a constructor argument of "Preview".

Cheers,
_

[arturs]

Could you give me an example this method and other method which are possible ?