String toCharArray returns weird fault code

Projects Programming
1

I've a simple sketch which should convert a basic string into a char Array. EasyPeasy Lemon pie and thx god or StarTrek that arduino support the string.toCharArray() method.

However, I receive weird error and sit here with no clue what is wrong.

void setup(){
Serial.begin(9600);
}


String  input = "TEST";
int input_length = input.length()+1;
char splitter[input_length];
input.toCharArray(splitter, input_length);

void loop()
{
 
  if(Serial.available() > 0)
    {
      input   = Serial.readString();
      input.toUpperCase();
    }
     
     Serial.println(input);
     delay(500);
   
}

Error Code

sketch_dec05b:10: error: array bound is not an integer constant before ']' token
 char splitter[input_length];
                            ^
sketch_dec05b:11: error: 'input' does not name a type
 input.toCharArray(splitter, input_length);
 ^
exit status 1
array bound is not an integer constant before ']' token

So what the heck did I wrong ???

2

Well what you did wrong is using the String class for something so basic so you are punished :slight_smile:

Besides that try declaring

[color=red]const[/color] String  input = "TEST";

[color=red]const[/color] int input_length = input.length()+1;

If you insist using the String class you might want to look at the c_str() function (this gives direct access to the internal String buffer and should be used with care. In particular, you should never modify the string through the pointer returned)

3

If you insist using the String class you

can forget getting help here!

4

Found the mistake...was not placed inside the loop :grin: