character input for an integer variable? Im trying out the code found here , let me quote the section of code that bothers me.

// set pin numbers for switch, joystick axes, and LED:
const int switchPin = 2;      // switch to turn on and off mouse control
const int mouseButton = 3;    // input pin for the mouse pushButton
const int xAxis = A0;         // joystick X axis
const int yAxis = A1;         // joystick Y axis
const int ledPin = 5;         // Mouse control LED


xAxis is a variable that is defined as an integer , however, it is being assigned a character(A0), How is this possible? I tried to compile and run the code and everything works well. I'm quite surprised!
A0 and A1 are not characters or what you mean probably: strings.
Because it would be written as "A0" and "A1".
The types of A0 and A1 are probably integers or another numeric type.

However, these are probably defined as (constant) integers, e.g.:

const int A0 = 100;
const int A1 = 101;


(note 100 and 101 are random numbers)

or defined by a macro. e.g.:

#define A0  100
#define A1  101


So the variables A0 and A1 are actually integers (or assigned as numeric values by a define).