Fix numberOfTaps in the example

[timbotimbo]

The example contains a tap counter, that never increments as intended.

This is caused by using ++ in _numberOfTaps++.

From the docs

++var	var  =  var + 1 (expression value is var + 1)
var++	var  =  var + 1 (expression value is var)

I've simply changed it to += 1 for clarity.

- _numberOfTaps = _numberOfTaps++;
+ _numberOfTaps += 1;