Expected ')' before numeric constant

Projects Programming
1

Hi all! I am new returning to coding after ~20 years and I find myself stuck on likely a very basic issue...

I am trying to use 2 push buttons to control in and out on an actuator and do not undestand why i am getting error "expected ')' before numeric constant" on my 4th line of code as seen below:

 #define BUTTON_PIN 2
 #define BUTTON_PIN 3
int outButtonState = digitalRead(BUTTON_PIN 3);
int inButtonState = digitalRead(BUTTON_PIN 2); // ERROR IS WITH THIS LINE

Please advise with out beating me up too much... lol

Thanks in advance.

2

this defines BUTTON_PIN to 2 and then the next line defines it as 3.

the space matters.

did you mean BUTTON_PIN_2 2?

3

The syntax of define means - "define a macros BUTTON_PIN and set its value to 2"

So the two lines at beginning of your code defines the same macros BUTTON_PIN twice. If you need to define a two pins, the names must not be the same.
For example:

#define BUTTON_PIN1 2
#define BUTTON_PIN2 3

Than, when you use the macro in the code, you must place only the name rather than "name value" pair. So the correct variant of your 4th line will be:

4

Thanks for the feedback b707. That is odd as even if i change them to say:

#define BUTTON_PIN_IN 2
#define BUTTON_PIN_OUT 3

I get the same error. Does that make sense?

5

You wrote above that you got an error in 4th line. Did you changed it? Please show your code in full

6

Yes. As I responded to b707:

Even if I define them as:

#define BUTTONPIN_IN 2
#define BUTTON_PIN_OUT 3

I get the same error.

7

Please show your code

8

why are there 2 separate values: BUTTON_PIN and 3, being passed as arguments? there should only be one

digitalRead (BUTTON_PIN);
9 
#define BUTTON_PIN_2 2
#define BUTTON_PIN_3 3
int outButtonState = digitalRead(BUTTON_PIN_3);
int inButtonState = digitalRead(BUTTON_PIN_2);
10

Part of using # define or other ways to give names to numbers is to... leave the numbers behind, and to make one place where the identifier <-> number translation is done, in the case you want to change your wiring, or TBH to fix mistakes in software instead of hardware, like:

#define BUTTON_A 2
#define BUTTON_B 3

int outButtonState = digitalRead(BUTTON_B);
int inButtonState = digitalRead(BUTTON_A);

a7

11

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