How to use object of one class in another one

rezaMSLM

in my project I have two classes: "MainWindow" and "secwindow"
my MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QtNetwork/QFtp>
#include "secwindow.h"
namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
   
    ~MainWindow();

private slots:
.
.
.
private:
    Ui::MainWindow *ui;
    SecWindow *secWindow;
    QFtp *ftp;
    .
   .

};

#endif // MAINWINDOW_H

my secwindow.h:

#ifndef SECWINDOW_H
#define SECWINDOW_H

#include <QDialog>
#include <QFile>
//#include "mainwindow.h"
namespace Ui {
class SecWindow;
}

class SecWindow : public QDialog
{
    Q_OBJECT

public:
    explicit SecWindow(QWidget *parent = 0);
    ~SecWindow();

private slots:
    void on_pushButton_write_values_clicked();

private:
    Ui::SecWindow *ui;
    QFile *myfile;
    QString s1,s2,s3,s4,s5,s6,s7,s8,s9;

};

#endif // SECWINDOW_H

How I can use "ftp" in secwindow?

VRonin

This question has been asked a million times.
You don't use it.
SecWindow should emit a signal, MainWindow will pick up the signal and use ftp.

P.S.
If you are using Qt5 avoid QFtp. It's unsupported and outdated

TheTugaOne

You question "How I can use "ftp" in secwindow?" is rather vague. Depending on your needs you can use pointers or references to pass the "ftp" object to "SecWindow" . If you don't need a reference to the object you can definitely take a look at VRonin's answer in more detail here http://doc.qt.io/archives/qt-4.8/signalsandslots.html .