How i can plot result in my GUI ?

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Hello world,

i have raed a tutorial which it speak about curve with QWT. In this tutorial i find this example to plot a curve during compilation:


this is the code:

#include <QApplication>
#include <qwt_plot.h>
#include <qwt_plot_curve.h>
 
int main(int argc, char** argv)
{
    QApplication app(argc,argv);
    QwtPlot myPlot;
    QwtPlotCurve myCurve;
 
    myCurve.attach(&myPlot);
 
    QVector<double> x(5);
    QVector<double> y(5);
 
    for(int i=0;i<5;i++)
    {
        x.append((double)i);
        y.append((double)(5-i));
    }
    myCurve.setData(x.data(),y.data(),x.size());
 
    myPlot.replot();
    myPlot.show();
    return app.exec();
}

#include <QApplication>
#include <qwt_plot.h>
#include <qwt_plot_curve.h>

int main(int argc, char** argv)
{
    QApplication app(argc,argv);
    QwtPlot myPlot;
    QwtPlotCurve myCurve;

    myCurve.attach(&myPlot);

    QVector<double> x(5);
    QVector<double> y(5);

    for(int i=0;i<5;i++)
    {
        x.append((double)i);
        y.append((double)(5-i));
    }
    myCurve.setData(x.data(),y.data(),x.size());

    myPlot.replot();
    myPlot.show();
    return app.exec();
}

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this is the error:

==> see attached file

i don't why arguments are not good...

how i can plot this curve please?

thank you for your help

(the help of QWT is very difficult for my, i am a real beginner, it is the reason why i ask this)