I have just realised that in pset4's short named "click" (at 2.30) here David prints out the coordinates of the click as floating point numbers. The number of pixels is finite so they could be integers. I do not see any reason to make them floats or doubles as it is also in other cases.
I have just watched that short video again. David speaks about pixels. So, the question stays. Why using variable of double type for storing number of pixels?
Can somebody explain me this?