Member show is non-class type 'MainWindow()'

[t0msk]

Hello, I would like to ask you about this error:

error: request for member 'show' in 'w', which is of non-class type 'MainWindow()'

and this is code:

QScopedPointer<QCoreApplication> app(createApplication(argc, argv, data));

if (qobject_cast<QApplication *>(app.data())) {
        MainWindow w();
        w.show();
}

return app->exec();

What is wrong with it, please?

[VRonin]

MainWindow w();

declares a function that takes no arguments and returns a MainWindow. This is one of the ambiguities the C++11 brace constructor removed.

Use either MainWindow w; or MainWindow w{};

[t0msk]

@VRonin Thank you I changed it to MainWindow w; but there is another problem:

error: no matching function for call to 'MainWindow::MainWindow()'

[SGaist]

Hi,

Can you show the header and code of your MainWindow class ?

[t0msk]

mainwindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "about.h"
#include "settings.h"

#include "QHash"
#include "QFile"
#include "QCryptographicHash"
#include "QDebug"

QByteArray fileChecksum(const QString &fileName, QCryptographicHash::Algorithm hashAlgorithm)
{
    QFile f(fileName);

    if (f.open(QFile::ReadOnly)) {

        QCryptographicHash hash(hashAlgorithm);

        if (hash.addData(&f)) {
            return hash.result();
        }
    }
    return QByteArray();
}

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

MainWindow::~MainWindow()
{
    delete ui;
}


void MainWindow::on_actionAbout_triggered()
{
    About about;
    about.setModal(true);
    about.exec();
}

void MainWindow::on_actionSettings_triggered()
{
    Settings settings;
    settings.setModal(true);
    settings.exec();
}

mainwindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QHash<QString, QString>, QWidget *parent = 0);
    ~MainWindow();

private slots:
    void on_actionAbout_triggered();

    void on_actionSettings_triggered();

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

[aha_1980]

Hi @t0msk,

in your header you have: explicit MainWindow(QHash<QString, QString>, QWidget *parent = 0); but in your C++ file you have: MainWindow::MainWindow(QWidget *parent).

That does not fit, and it does especially not fit your MainWindow w; in the main.cpp file.

Regards

[SGaist]

@t0msk said in Member show is non-class type 'MainWindow()':

explicit MainWindow(QHash<QString, QString>, QWidget *parent = 0);

You have a mandatory parameter here. Since you don't provide it it can't work.

[t0msk]

@aha_1980 @SGaist Ahh sorry, I forgot to remove it ^^ because I was changing code :) Thank you :)