undefined reference Error in helloworld program !

[high_flyer]

change QCoreApplication to QApplication. - and the corresponding include as well.

[prady]

Hi,

Thanks for quick reply, but the solution is not working for me !
now the code is changed to

#include <QApplication>
#include <QtGui\QLabel>
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
 
    QLabel label("Hello World!");
    label.show();
 
    return a.exec();
}

#include <QApplication>
#include <QtGui\QLabel>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QLabel label("Hello World!");
    label.show();

    return a.exec();
}

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but i am getting the following errors:

main.cpp:1:24: error: QApplication: No such file or directory

main.cpp:6: error: variable 'QApplication a' has initializer but incomplete type

when I choolse "Qt Console Application", while creating new project, by default QtCreator includes QtCoreApplicaion. so is that wrong ?

-Pradeep-

[high_flyer]

#include <QtGui\QApplication>

when I choolse "Qt Console Application", while creating new project, by default QtCreator includes QtCoreApplicaion. so is that wrong ?

No, QtCreator is doing it right.
But a console application by definition has no GUI. (I am not talking about ncourses style GUI).
Yet you are initializing gui elements in your code!
So either use GUI and make a GUI application, or a console one, without GUI.
But trying to use GUI elements in non GUI application wont work.

[prady]

Yes I understand now, thank you.

but only adding #include <QtGui\QApplication> is not fixing my problem.
I have modified "QT -= gui" line in .pro file to "QT += gui" helps to solve those errors.

I assume this tells compiler to include gui libraries.

Thanks again,
Pradeep.

[high_flyer]

yes, that is correct.
In my first answer I was not aware you configured a console application.