simple character versus string question

Projects Programming
1

In an application

#define IDENTIFIER 'A'

is used. However, the same A needs to be converted to a string.
So instead of having to write

char a[] = "A";

I would like to use the variable in IDENTIFIER to be read into the string array.
How best to write this?

2 
#define IDENTIFIER 'A'
char a[] = IDENTIFIER ;
3

Idahowalker:

#define IDENTIFIER 'A'

char a[] = IDENTIFIER ;

TOP!!
Thank you,
Erik

4 
char a[] = {IDENTIFIER, '\0'} ;
5

Variables are not defines and defines are not variable.

Declaration of a variable is for informing to the compiler the following information: name of the variable, type of value it holds and the initial value if any it takes. i.e., declaration gives details about the properties of a variable. Whereas, Definition of a variable says where the variable gets stored. i.e., memory for the variable is allocated during the definition of the variable.

6

I now understand that a define is not a variable.
But I still want to read this IDENTIFIER into an array a[].

I received two answers:

char a[] = IDENTIFIER;

and

char a[] = {IDENTIFIER, '\0'};

What should it now best be?

7

brice3010:
I received two answers:

char a[] = IDENTIFIER;

and

char a[] = {IDENTIFIER, '\0'};

What should it now best be?

Depends on what you want to do with it.

8

gfvalvo:
Depends on what you want to do with it.

Send as an array:

  LoRa.write((const uint8_t*)&a, sizeof(a));
9

If you need to treat it as a c-string, then add the null terminator. If not, don't.

10

gfvalvo:
If you need to treat it as a c-string, then add the null terminator. If not, don't.

Compiling only works if this is used:

char a[] = {IDENTIFIER, '\0'};

If not, an error says that the size of IDENTIFIER could not be determined.

11

Can't see why. This compiles:

#define IDENTIFIER 'A'
char a[] = {IDENTIFIER};

void setup()
{
  Serial.begin(115200);
}

void loop()
{
}
12

wildbill:
Can't see why. This compiles:

#define IDENTIFIER 'A'

char a[] = {IDENTIFIER};

void setup()
{
 Serial.begin(115200);
}

void loop()
{
}

My apologies!! I had forgotten the parenthesis { and }

13

Doesn't the gcc pre-processor have a "stringify" operator to do exactly what the OP is asking for?

14

brice3010:
My apologies!! I had forgotten the parenthesis { and }

No need to apologise - that's what was in reply #1.

15

RayLivingston:
Doesn't the gcc pre-processor have a "stringify" operator to do exactly what the OP is asking for?

It does, but I'm not certain that's what the OP is asking for.

16

TheMemberFormerlyKnownAsAWOL:
It does, but I'm not certain that's what the OP is asking for.

If I knew what a gcc-preprocessor or stringify operator areI would answer.

However, using the code above in answer to my question, I do get the correct value at the LoRa receiver.

17

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