Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!amelia!msf
From: msf@amelia.nas.nasa.gov (Michael S. Fischbein)
Newsgroups: comp.lang.fortran
Subject: Re: Modifying iteration variables in DO loops
Message-ID: <162@amelia.nas.nasa.gov>
Date: 2 Feb 88 12:14:30 GMT
References: <1309@nmtsun.nmt.edu>
Reply-To: msf@amelia.nas.nasa.gov (Michael S. Fischbein)
Organization: NASA Langley Research Center, Hampton, VA
Lines: 15
Keywords: X3 standard FORTRAN 77
Summary: Check the standard again.

In article <1309@nmtsun.nmt.edu> john@nmtsun.nmt.edu (John Shipman) writes:
>In section 11.10 of X3.9-1978, the FORTRAN 77 standard (pp. 11-5 to
>11-9), there is no statement about prohibiting the modification of a
>DO variable within a loop.

From ANSI X3.9-1978 FORTRAN 77, page 11-8, section 11.10.5, line 6:
  ``Except by the incrementation described in 11.10.7, the DO-variable of
    the DO-loop may neither be redefined nor become undefined during ex-
    ecution of the range of the DO-loop.''

Section 11.10.7 describes how the DO-loop's incrementation processing works.
-- 
Michael Fischbein                 msf@ames-nas.arpa
                                  ...!seismo!decuac!csmunix!icase!msf
These are my opinions and not necessarily official views of any
organization.