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From: jlg@lanl.gov (Jim Giles)
Newsgroups: comp.lang.fortran
Subject: Re: FORTRAN porting question
Message-ID: <11488@lanl.gov>
Date: 4 Apr 89 21:18:21 GMT
References: <16715@mimsy.UUCP>
Distribution: usa
Organization: Los Alamos National Laboratory
Lines: 27

From article <16715@mimsy.UUCP>, by chris@mimsy.UUCP (Chris Torek):
> In article <11447@lanl.gov> jlg@lanl.gov (Jim Giles) suggests two
>>C     NOTE: THIS ONE MAY FAIL DUE TO K BEING UNDEFINED AT THIS POINT.
>>      IF (I.EQ.J) GOTO 1000
>>      ...
>>      K=0
>>  999 K=K+1
>>      ...
>> 1000 IF (K.LT.77) goto 999
> 
> (minor bug: should be k .le. 77) [...]

Not true.  If the condition were set to (K.LE.77) instead of (K.LT.77),
the body of the loop would be executed with K==78.  That would be one too
many times.  You are right, however, that the more common desired inter-
pretation of the loop would be:

C     NOTE: THIS ONE MAY FAIL DUE TO K BEING UNDEFINED AT THIS POINT.
      IF (I.EQ.J) GOTO 1000
      ...
      K=1
  999 ...       ! BODY OF LOOP
      K=K+1
 1000 IF (K.LE.77) goto 999

The reason for prefering this would be that the value of K after the
loop would be 78, just like the DO-loop would have left.