qwt several curves at a plot

I have a problem using the member function attach several times. I have attached many curves, than I make replot. As a result, only last attached curve is visible. Compiler does not find any errors. Here is my member function which draws several characteristics stored in ps_x and ps_y sequentially in the single column. The number of characteristics equals number_of_characteristics. I use qwt 6. version.

Code:

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void DataPlot::plot_Draw(double ps_x[], double ps_y[], double x_min, double x_max, double y_min, double y_max, int number_of_characteristics)
{
	double psx[1500];
	double psy[1500];
 
	setAxisScale(QwtPlot::xBottom, x_min, x_max);
	setAxisScale(QwtPlot::yLeft, y_min, y_max);  
 
	QwtPlotCurve *d_curves[number_of_characteristics];
 
	for (int j=0;j<number_of_characteristics;j++){
 
		d_curves[j] = new QwtPlotCurve("Gain spectra");
		d_curves[j]->setRenderHint(QwtPlotItem::RenderAntialiased);
		d_curves[j]->setPen(QPen(QColor(150,150,200),2));
		d_curves[j]->setStyle(QwtPlotCurve::Lines);
 
		for (int j1=0;j1<1500;j1++){
			psx[j1]=ps_x[j1+j*1500];
			psy[j1]=ps_y[j1+j*1500];
		};
		// Insert new curves		
		d_curves[j]->setRawSamples(psx,psy,1500);
		d_curves[j]->attach(this);  
	};
	replot(); 	
}

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Probably this, from docs on QwtPlotCurve::attach

Quote:

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Attach the item to a plot.

This method will attach a QwtPlotItem to the QwtPlot argument. It will first detach the QwtPlotItem from any plot from a previous call to attach (if necessary). If a NULL argument is passed, it will detach from any QwtPlot it was attached to.

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Use setSamples instead of setRawSamples.

Uwe

Thank you Uwe! setSemples works perfect in my case.

What is difference between these functions? Where can I find tutorial for qwt 6.0. ?

Quote:

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Originally Posted by freude3

Yes, but how does in this case can the demo "sinusplot" works?

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The bad code assigns memory from the stack without copying it. What has this to do with the sinusplot example - that uses a synthetic data class without storing arrays at all.

Uwe