Calling a function with just some of the parameters

[syka2210]

From my old memory, in C++ whenever I wanted to use a basic function that had multiple parameters, and wanted to use just some of them I just used something like this.

Void example(int nr=0, char let='z', String message="") 

Void setup() {
} 

Void example(int nr, char let, String message) {
  doing maggic;
} 

Int main() {
 if (sunny outside == true) {
    example(nr=5, message="sun") ;
} 

I create the parameters and allocate them some values, in order to be... Not empty. After that, I would call the function specifying what values I want to send, and other than that, those values would remain as set.
When compiling the code, arduino ide tells me the parameters where not declare in that scope. I am not sure if I'm missing something, or if the compiler does not accept this way of handling what I am trying to accomplish.

[Danois90]

This is C and not Python, this is how sendToSerial should be called:

sendToSerial("", "abs");

EDIT: And if you are using an AVR based MCU, you should not use the "String" data type at all.

[syka2210]

But how will the function know which parameter I want the value assigned to? For example if I'm having 5 int, 3 char, 2 bool, and I'm just sending 2 int, 1 char and 1 bool?
Or for the other parameters that I'm not interested in I have to mandatory send some values?

[Paul_KD7HB]

@syka2210

But how will the function know which parameter I want the value assigned to?

It won't unless you wrote the function to tell it that information. The parameters are assigned in sequence.

[Danois90]

You will have to specify all parameters from left to the one you want to use:

void doit(arg1 = 0, arg2 = "", arg3 = 0, arg4 = "") { whatever.. };

//Only using arg2
doit(0, "something");

//Only using arg4
doit(0, "", 0, "something");

//Only using arg1
doit(123);

What you tried in the posted image i Python syntax which does not work in C(++).

[syka2210]

Thank you, that's helpful. Also I'm invading a Rp2040, so I would believe it could handle the String nicely, since I using a lot of text, and using char arrays would be a nightmare for me