Path: utzoo!utgpu!utstat!jarvis.csri.toronto.edu!mailrus!uflorida!ufqtp!bernhold
From: bernhold@qtp.ufl.edu (David E. Bernholdt)
Newsgroups: comp.lang.fortran
Subject: DO loops, anyone?
Message-ID: <458@orange19.qtp.ufl.edu>
Date: 11 Mar 89 15:49:54 GMT
Reply-To: bernhold@qtp.ufl.edu (David E. Bernholdt)
Organization: University of Florida Quantum Theory Project
Lines: 49


I run the following code on my Sun 3/50 with VMS compatible f77:

      PROGRAM LOOP
      IGO = 1
      DO 501 I = 1, 10
         WRITE (6,*) 'OUTER LOOP, I =',I
         IF (IGO .NE. 0) GOTO 501
         DO 501 J = 1, 5
            WRITE (6,*) 'INNER LOOP, J=',J
 501     CONTINUE
         STOP
         END

And I get the following output:

  OUTER LOOP, I =  1
  INNER LOOP, J=  1
  INNER LOOP, J=  2
  INNER LOOP, J=  3
  INNER LOOP, J=  4
  INNER LOOP, J=  5
  OUTER LOOP, I =  2
  OUTER LOOP, I =  3
  OUTER LOOP, I =  4
  OUTER LOOP, I =  5
  OUTER LOOP, I =  6
  OUTER LOOP, I =  7
  OUTER LOOP, I =  8
  OUTER LOOP, I =  9
  OUTER LOOP, I =  10

Notice that the inner DO loop is executed exactly once.

My questions are these:

1) Is the code standard-conforming?  I think it is, but perhaps I am
mistaken.

2) If the code is standard-conforming, is the execution correct?  As
far as I can tell, the inner DO should never be activated!

Please, no flames about the code itself.  I did not write it - I just
get to port it.
-- 
David Bernholdt			bernhold@qtp.ufl.edu
Quantum Theory Project		bernhold@ufpine.bitnet
University of Florida
Gainesville, FL  32611		904/392 6365