Stereo Calibration sample bug?

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Hello to all! I'm writing here because i can't understand a line of the opencv c++ sample stereo calibration program: https://github.com/Itseez/opencv/blob/master/samples/cpp/stereo_calib.cpp , line number 161:

for( i = 0; i < nimages; i++ )
{
    for( j = 0; j < boardSize.height; j++ )
        for( k = 0; k < boardSize.width; k++ )
            objectPoints[i].push_back(Point3f(j*squareSize, k*squareSize, 0));
}

It is the piece of code that calculates the calibration points coordinates in calibration object frame of reference. I can't understand why, when calibration object points are calculated, the point coordinates are (j, k, 0): "j" is used for height, so, i don't understand why it is used as abscissa, and viceversa for k. In my humble opinion, it is a bug and it should be:

objectPoints[i].push_back(Point3f(k*squareSize, j*squareSize, 0));

I've used Google and found that in EmguCV example (http://www.emgu.com/wiki/index.php/Stereo_Imaging), the code is:

for (int i = 0; i < height; i++)
{
    for (int j = 0; j < width; j++)
    {
      object_list.Add(new MCvPoint3D32f(j * 20.0F, i * 20.0F, 0.0F));
    }
}

and this makes me think that i could be right. But I'm not sure, so I'm asking you: I'm right or wrong? And if I'm not right... can you please explain me why?

Thanks in advance