2D array data plot!

[kahramonj]

Hi QWT Forumers!

I'd like to draw 2d array data and it is my first experience with QWT, everything is OK, but the following code is drawing only ONE(last) curve. Dear fellowship, please help !

Plot::Plot()
{
    setTitle("A Simple QwtPlot Demonstration");
    insertLegend(new QwtLegend(), QwtPlot::RightLegend);
 
    // Set axis titles
    setAxisTitle(xBottom, "x -->");
    setAxisTitle(yLeft, "y -->");
 
    // Insert new curves
    QwtPlotCurve *cSin = new QwtPlotCurve("y = sin(x)");
    #if QT_VERSION >= 0x040000
    cSin->setRenderHint(QwtPlotItem::RenderAntialiased);
    #endif
    cSin->setPen(QPen(Qt::red));
    cSin->attach(this);
 
    const int nPoints = 100;
    double x[2][nPoints], y[2][nPoints];
    for(int j=0; j<2; j++)
    {
      for(int i=0; i<nPoints; i++) 
      {
        x[j][i] = -3.14 + i*(j+2)*3.14/(nPoints-1);
        y[j][i] = sin((j+1)*x[j][i]);    
      }
    }
 
    // Create 2d array data        
    for(int j=0; j<2; j++)
      cSin->setData(x[j],y[j],nPoints);
 
}

Plot::Plot()
{
    setTitle("A Simple QwtPlot Demonstration");
    insertLegend(new QwtLegend(), QwtPlot::RightLegend);

    // Set axis titles
    setAxisTitle(xBottom, "x -->");
    setAxisTitle(yLeft, "y -->");
    
    // Insert new curves
    QwtPlotCurve *cSin = new QwtPlotCurve("y = sin(x)");
    #if QT_VERSION >= 0x040000
    cSin->setRenderHint(QwtPlotItem::RenderAntialiased);
    #endif
    cSin->setPen(QPen(Qt::red));
    cSin->attach(this);

    const int nPoints = 100;
    double x[2][nPoints], y[2][nPoints];
    for(int j=0; j<2; j++)
    {
      for(int i=0; i<nPoints; i++) 
      {
        x[j][i] = -3.14 + i*(j+2)*3.14/(nPoints-1);
        y[j][i] = sin((j+1)*x[j][i]);    
      }
    }

    // Create 2d array data        
    for(int j=0; j<2; j++)
      cSin->setData(x[j],y[j],nPoints);
   
}

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