What data type are the analog pin labels (A0, A1, etc)?

Question

Arduino Mega

I would like to have an array containing analog pin labels something like...

int analog_pins[] = {A0, A1, A2, A3};
int num_analog_pins = sizeof(analog_pins) / sizeof(analog_pins[0]);

Is this possible? It has compiled without any warnings or errors but I'm dont have my board with me (yes beginners mistake) so cant really check if it works.

Answer 1

As you can see in Arduino.h, the analogRead() has uint8_t as parameter. You can define them as byte or uint8_t and you don't have to use the sizeof().

The type of A0 is defined in the file pins_arduino.h:

#define PIN_A0 (14)
static const uint8_t A0 = PIN_A0;

Nevertheless, what you have with integers is 100% okay as well.

When you don't have a Arduino board available, you can use the simulation of an Arduino Uno at Tinkercad.

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As @DataFiddler writes below this answer, using a 'const' keyword is preferred:

const uint8_t analog_pins[] = {A0, A1, A2, A3};

Answer 2

Your calculation will be correct for num_analog_pins, however it's convention to use the type of the array like so

int num_analog_pins = sizeof(analog_pins) / sizeof(int);

As @Jot noted, you'd save much space by declaring your array using uint8_t like so

uint8_t analog_pins[] = {A0, A1, A2, A3};
uint8_t num_analog_pins = sizeof(analog_pins) / sizeof(uint8_t);