Re: How do you read this code ?

[Joe Pluta <joepluta@xxxxxxxxxxxxxxxxx>]

Cyndi Bradberry wrote:
>      C     TTBAST        IFNE      'D'
>      C     TTA9CD        ANDNE     '001'
>      C     TTA9CD        ORNE      '002'
>      C     TTA9CD        ORNE      '003'
>      C     TTA9CD        ORNE      '012'
>      C     TTA9CD        ORNE      '013'
>      C     TTBAST        ORNE      'H'
>      C     TTA9CD        ANDNE     '   '
>      C                   MOVE      TTOFCD               OFCD      2
>
> We have run across  this code in a very old program we are trying to
> bring into the current century.
>
> If you were to rewrite this using parenthesis.....how would you group
> things ?  We dragged out the manual on the order of resolving equations,
> but it really doesn't help us much.
>   
If I were to rewrite this, I'd write:

OFCD = TTOFCD;

Huh?  No IF?  No, no if.

Because each group separated by OR is evaluated separately, and the code 
is executed if any group evaluates to true.  Now, check carefully: two 
of the groups are TTA9CD NE 002 and TTA9CD NE 003.  If you think about 
it a moment, you should see that one of those is ALWAYS true (and 
sometimes both).  TTA9CD can neverbe both 002 and 003, so one of the NE 
tests will fail.

This code is a big, huge, IF 1 = 1.

Joe