Q:

Understanding analog pins in pinMode

When passing the pin number in pinMode its possible to use A0 - A7, does it apply only to that methode? 
How can pinMode expect a number (is it int?) type in case of digital pin another (is it then string?) in case of analog pin?
I want to use that in my class methode, is there a way to use that and have my code more readable or should I use the pin numbers?
P.S. I have tried to read the source code but I don't understand the uin8_t (I know its a byte, but not how it can understand A5 as an int)
Tnx a lot

A:

pinMode is actually declared as void pinMode(uint8_t, uint8_t);  in arduino.h
A0 is a defined as a number (somewhere depending on the actual hardware), on an Uno/Nano it translates to 14, and when executing pinMode it translates to the appopriate bit in the correct DDRx register. 

