Perform varying // for - array in cobol

[voicucosmin90]

Hi guys,
I have a question if you could me help with these:
I want to implement in cobol a repetitive structure like these:
for i = 1 to n
execute different instructions
end-for
-----
I make something like these:
01 n pic 9(2) value 1.
01 ws-x.
05 ws-a pic x(500) occurs 1000 times.
indexed by n.
---
perform varying i from 1 by 1 until i > n
//different instructions
end-perform
..
but I have some errors for n when I compile, I get LNC1463 " 'N' is not unique in this context"
How I can resolve these? please help me with some info regarding for in cobol and how I can arrive to the end in perform varying structure, I'm newbie in cobol :P, thanks in advance.

[TedHolt]

Re: Perform varying // for - array in cobol

Don't define N at the 01 level. The system defines it automatically.

[tomliotta]

Re: Perform varying // for - array in cobol

The COBOL manual describes the INDEXED BY clause with this: "These index-names are not data-names, and are not identified elsewhere in the COBOL program...". When you code an INDEXED BY clause, the clause defines the index variable as a special data type. You can't define a variable with the same name in the same scope.

That's about all there is to it.