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From: gt4512c@prism.gatech.EDU (BRADBERRY,JOHN L)
Newsgroups: comp.lang.fortran
Subject: Re: Is this kosher?
Message-ID: <20773@hydra.gatech.EDU>
Date: 30 Jan 91 12:12:44 GMT
References: <2787@dftsrv.gsfc.nasa.gov>
Organization: Georgia Institute of Technology
Lines: 38

In article <2787@dftsrv.gsfc.nasa.gov> jim@jagubox.gsfc.nasa.gov (Jim Jagielski) writes:
>
>Tell me, is jumping into an IF block statement legal (I know it ain't
>pretty)... for example:

The program fragment suggested produces the following output
(modified and using a Microsoft 5xx Compiler):

    15        
    16        if (value .lt. 0) then
    17          COUNT=12345
    18        else
    19  22      COUNT=0
    20        end if
    21        
    22        if (a.lt.b) goto 22
***** XXX.FTN(22) : warning F4801: label 22 : used across blocks
    23        

In general, this is NOT considered good programming practice and
usually leads to code that is difficult to maintain and modify.
To quote Michael Metcalf (c) 1985-88, author of "Effective Fortran 77",
Oxford University Press (page 44),

"The statements within an IF block may be labelled, but
the labels must never be referenced in such a fashion
as to pass control into the range of an IF block or
ELSE clause ..."

When faced with an urge to do something like this, take a deep
breath, get a beverage, and RE-THINK your logic. The next person
to 'fix' your code will thank you!

-- 
John L. Bradberry        |Georgia Tech Research Inst|001100110011001100110011
Scientific Concepts Inc. |Microwaves and Antenna Lab|Int : gt4512c@prism
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