Topic: ARRAY idexed by ENUM value

Hi all,
I'm working with ARRAY indexing and I get some problems. I'm used to work with C and there I define and ENUM with indexes like this:

TYPE INDEX :
(
    ID1,    //0
    ID2,    //1
    ID3,    //2
    NELEM := 3
);
END_TYPE

Then I generally declare an ARRAY with "NELEM" as size. In CODESYS is quite difficult, because if I write

    values : ARRAY [0..INDEX.NELEM] OF INT;

the array has 4 elements, not 3.

If I write

    values : ARRAY [1..INDEX.NELEM] OF INT;

the array has 3 elements, but INDEX.ID1 has no location, because the index in the array starts from 1.

I can't write

    values : ARRAY [0..INDEX.NELEM-1] OF INT;

because of error C0359: Arithmetics not allowed on strict ENUM type '...'.

I read this topic:
https://forge.codesys.com/forge/talk/Engineering/thread/f237737cda/

but has no good solutions. The only remaining solution of that topic is to have unused array locations, but safety rules (for safety programming) generally state to avoid unused variables and empty location.

Any other ideas?
At now I probably define global variables, but it is an error-prone solution.

Francesco

Welcome Francesco,

this works for me:

{attribute 'qualified_only'}
{attribute 'strict'}
TYPE INDEX :
(
    ID1,    //0
    ID2,    //1
    ID3,    //2
    {warning disable C0125}
    LASTELEM := ID3
    {warning restore C0125}
);
END_TYPE

PROGRAM POU
VAR
    values : ARRAY [0..INDEX.LASTELEM] OF INT;
END_VAR

values[INDEX.ID1] := 1;
values[INDEX.ID2] := 10;
values[INDEX.ID3] := 100;