String variabe array too large

Projects Programming
1

I have a variable declared as a String array

String SubSelectorArray[10][6] = {{"3.500 MHz","7 MHz", "14 Mhz", "21 MHz", "28 MHz",""},

The String is passed to a function

int RotarySelector(String strOption) 
{

When the array was size [10][6] the function did not receive the variable and flagged it as empty string which I do check for. For test purpose I reduced the array to [5][6] and have no issues passing the string to the function.
Obviously I pushed the Uno something ( memory?) , using over 50% of dynamic memory, over some limit.

Two questions - what or how can I check for whatever I am exceeding to prevent chasing stuff like this using String?
And what exactly this note means - is it String or char?

[/quote]

For reference, character arrays are referred to as strings with a small s, and instances of the String class are referred to as Strings with a capital S. Note that constant strings, specified in "double quotes" are treated as char arrays, not instances of the String class.

Thanks for your time, appreciate any constructive help.
Vaclav

2

Dont use Strings, use char pointer arrays.

char * data[5] = {
  "Hello ", "this ", "is ", "a ", "test."};

void setup()
{
  Serial.begin(9600);
  for(int i =0; i < 5; i++)
    Serial.print(data[i]);
}

void loop() { }
3

Thanks,
I have no problem doing that.
I feel " wrappers" are OK but should not be build this sloppy way. Not the first strange encounter.
Cheers
Vaclav

4

The Arduino has issues with Strings, so we try to steer people away from using them, and get them into the habit of using char arrays instead.

5

The static allocation of RAM for the protected variables for a 10x6 array of Strings is over 400 bytes before you even assign any data to them.
If all you're doing is having a bunch of labels that you'll only ever need to change by recompilation, flash (PROGMEM) is a much more sensible option.