Hidden problem with REDIM ?

[Nathan Maddox]

or just undocumented feature?

I would expect 2 subscript out of ranges (Error 9) on this code, but with
PB 9.0 I do not get any....

What do you think?

#COMPILE EXE
#DIM ALL

FUNCTION PBMAIN () AS LONG
    LOCAL I AS LONG
    LOCAL Temp$()

    REDIM Temp$(2)                                 '-----2 NOT 3 --------
    Temp$(1)="HELLO"
    Temp$(2)="PowerBasic"
    Temp$(3)="Hero"                                 '---Expect Subscript out of range
    IF ERR THEN ? "Err="+STR$(ERRCLEAR)
    
    FOR I=1 TO 3
        ? "Temp$("+STR$(i)+")="+Temp$(I) '--- Expect Error 9 on 3rd iteration
    NEXT
    IF ERR THEN ? "Err="+STR$(ERRCLEAR)

END FUNCTION

[Rodney Hicks]

From the documentation:

Error 9 will only be generated if you have specified #DEBUG ERROR ON.

[Nathan Maddox]

Ouch.

Thank you.

I looked for something like that in REDIM's documentation and it wasn't there.

Didn't occur to look elsewhere. (There's no other See also)

Thanks

Nathan

[José Roca]

REDIM Temp$(2) '-----2 NOT 3 --------

DIM and REDIM use a lower bound of 0 if you don't specify it. Therefore, with REDIM Temp$(2) you get an array of 3 elements (from 0 to 2). In BASIC, the "(2)" in your statement specifies the upper bound of the array, not the number of elements.

[Rodney Hicks]

The error text is terse when you first encounter it. I've found it helps to check out the error in the documentation, just to see what surprises are lurking there. I would think even more so when you don't encounter it and you think you should.

[Chris Holbrook]

If you want to loop through a whole array, then

    for i = lbound(arr()) to ubound(arr()) 
        ....
    next

is safest, as the code does not need to know what the array bounds are, which means that the actual array bounds are only specified in DIM or REDIM statements.