How does this do what it does (C++ classes, use of colon)

[sterretje]

Thanks for the extensive reply; plenty to study

@gcjr

not sure your question is about inheritance, passing array arguments, ...

I was about passing the array (and the use of the colon for that).

@gcjr

(& sym prevents passing null pts)

Interesting to know, I think I'm battling with that in another class that I'm writing; but that is for another topic.

@gcjr

the 3rd aspect is constructor vs begin(). seems that begin() make more sense if initialization needs to be postponed (e.g. after HW is initialized)

The begin() is clearly hardware related

@gcjr

another aspect is the array is maintained external to the class. an alternative would be to have an object for each pin

I wasn't happy with that either; I actually wanted to do what I do in structs (you can add function pointers to it simulating the virtual functions).

struct ABC
{
  const uint8_t pins[8];
  uint8_t value;
};

ABC someArray[] = 
{
  {{2,3,4}, 0},
  {{5,6,7}, 0},
};