hi i'm a new Qt user and i want to creat a new application that make a graph from csv file, so i used Qcustomplot to do so . but when i run the programm i have this message :
QCPGraph* QCustomPlot::addGraph(QCPAxis*, QCPAxis*) can't use default QCustomPlot xAxis or yAxis, because at least one is invalid (has been deleted)
QCPGraph* QCustomPlot::graph(int) const index out of bounds: 0
Le programme s'est terminé subitement.

here is my programm :

#include<Fenetre.h>
#include <QtWidgets>



MaFenetre::MaFenetre()
{
    setFixedSize(230,120);
    m_boutonDialogue = new QPushButton("importer",this);
    setCentralWidget(m_boutonDialogue);
    m_boutonDialogue->move(80,40);



    QObject::connect(m_boutonDialogue, SIGNAL(clicked()), this, SLOT(ouvrirDialogue()));



}

void MaFenetre::ouvrirDialogue()
{
    QString fichier = QFileDialog::getOpenFileName(this, "Ouvrir un fichier", QString());
    //QMessageBox::information(this, "ouvrir un fichier", fichier);
    QFile file(fichier);
        if (!file.open(QIODevice::ReadOnly))
        {
            qDebug() << file.errorString();

        }

        QStringList wordList,wordList2,wordList3,wordList4;
        while (!file.atEnd())
        {
            QByteArray line = file.readLine();
            wordList.append(line.split(';')[11]); // on recupere les valeurs de la 15 colonne
            wordList3.append(line.split(';')[9]);

        }
        wordList.removeFirst(); // on supprime le premier element(titre de la case)
        wordList3.removeFirst();
        wordList2 = wordList;
        wordList4 = wordList3;

        //qDebug() << wordList2;
        Graph(wordList2,wordList4);

}
void MaFenetre::Graph(QStringList x,QStringList y)
{
    QVector< QVector<double> > Vector1,Vector2;
    QVector< QVector<double> > *cVector1 = &Vector1;
    QVector< QVector<double> > *cVector2 = &Vector2;
    QVector<double> culomn1,culomn2;

    culomn1.clear();
    culomn2.clear();

    int dimension = x.count();
    int dimension2 = y.count();
    for(int i=0; i<dimension; i++)
    {
        culomn1.append( x.value(i).toDouble() );
    }
    for(int i=0; i<dimension2; i++)
    {
        culomn2.append( y.value(i).toDouble() );
    }
    qDebug()<< dimension;
    qDebug()<< dimension2;


    cVector1->append( culomn1 );
    cVector2->append( culomn2 );
    customPlot->addGraph();
    customPlot->graph(0)->setData(culomn1, culomn2);
    customPlot->xAxis->setLabel("x");
    customPlot->yAxis->setLabel("y");
    customPlot->xAxis->setRange(-1, 1);
    customPlot->yAxis->setRange(0, 1);
    customPlot->replot();

}

the programm works fine until he arrive to customplot->addGraph().
So can you please help me out with this ?
Thank you for the responses.