Re: 9/9/99

[Jim Langston <jlangston@xxxxxxxxxxxxxxxx>]

When I learned COBOL it was on a mainframe that used punch cards.
If you were reading data and you did not look for a "special" card you
coded with a "special" value, it would just read through the rest of the
deck, including any other programs after yours, thinking it was data.

If you did not enter the data in the format your read was expecting it,
you would get a run time error.

The solution was to put a "special" value in one of your fields.  If you were
reading string text, you could use *** EOF *** or something like that, but
if you were reading numeric fields,  you had to put in a numeric value, and
all 9's was commonly used, and was in fact called the "9's rule".

Jon.Paris@halinfo.it wrote:

>  >> From all the discussion I've heard on it, that was a common practice in
> COBOL programs as COBOL has no real EOF function (or didn't anyway).
>
> I don't recall any point in history when COBOL did not have an AT END option
> (i.e. EOF).  On some systems I have worked with placing a high value (all 9s) 
>in
> a dummy record at the end of file was done to allow you to position to
> (effective) EOF and read backwards - or is this what you meant by EOF 
>function ?
>
> Either way, it would never finish up as 09/09/99 it would have been 99/99/99.
>
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