Path: utzoo!attcan!uunet!ncrlnk!ncrcae!hubcap!gatech!uflorida!haven!adm!xadmx!abcscnuk%CSUNA.UUCP@cunyvm.cuny.edu
From: abcscnuk%CSUNA.UUCP@cunyvm.cuny.edu (Naoto Kimura)
Newsgroups: comp.lang.pascal
Subject: Control variables in FOR loops
Message-ID: <17843@adm.BRL.MIL>
Date: 16 Dec 88 19:18:10 GMT
Sender: news@adm.BRL.MIL
Lines: 51


    I have gotten into some pretty heated discussions regarding the
control variable in a for loop.  I was arguing that it was a bad idea to
use a global variable, in fact it is an error to do so.  I'm arguing
from the ISO standard, while the people I was arguing against were going
by specific implementations that allowed it.

    Should the use of a relatively global variable be allowed as a
control variable for a for loop ?  Should the use of a passed parameter
be allowed as a control variable ?  I say no to both of these.

    One person that I got into an argument with said that the behavior
should be that you can change a control variable, but should not have
any effect on the loop itself.  I don't think that is reasonable.
Consider the confusion over what the variable 'i' should contain when
you use it in several procedures as control variables for a for loop.

    I'd like to know how you feel about the behavior of the following
program.  What should the output be (if the compiler even lets this
code through) ?

program nonsense(input,output);
    var
    i : integer;

    procedure barf;
    begin
    for i := 1 to 10 do
        write(i:3);
    write('   i=',i)
    end;

    procedure ack;
    begin
    for i := 1 to 10 do begin
        write('i=',i:2,' ');
        barf;
        writeln
      end
    end;

begin
    for i := 1 to 10 do
    ack
end.

                //-n-\\                Naoto Kimura
        _____---=======---_____            (csun!csuna!abcscnuk)
    ====____\   /.. ..\   /____====
  //         ---\__O__/---         \\    Enterprise... Surrender or we'll
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