How to adjust my yData according to my Time scale

[rawfool]

I want to draw a dummy graph with time values on X-Axis with a increment of 15 seconds. On Y Axis, I'm passing data. I want the graph to set Y values to match x-values. But I'm unable to do so. I've copied the code in CpuPlot. But I couldn't make it work for my requirement.

curve = new QwtPlotCurve();
curve->setStyle(QwtPlotCurve::Lines);
curve->setCurveAttribute(QwtPlotCurve::Fitted, true);
curve->setRenderHint(QwtPlotItem::RenderAntialiased, true);


const double a[] = {12.30, 12.31, 12.32, 12.33, 12.34, 12.35, 12.36, 12.37, 12.38, 12.39, 12.4};
const double b[] = {880, 851, 822, 834, 845, 838, 810, 853, 814, 809, 800};

curve->setSamples(a, b, 11);
curve->attach(oParamGraph);

oParamGraph->setAxisScaleDraw(QwtPlot::xBottom, new TimeScaleDraw(cpuStat.upTime()));
oParamGraph->setAxisScale(QwtPlot::xBottom, 0, 165, 15);

With the above code, I'm getting the graph like this.
Graph1.jpg

Instead I want my graph to be like this. Which is aligned with respect to the const double b[] values like shown below
Graph2.jpg

How do I do?

Thank you.