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From: tada@athena.mit.edu (Michael J Zehr)
Newsgroups: comp.lang.c
Subject: Re: a style question
Summary: i vs. ix
Message-ID: <1990Oct23.160116.10299@athena.mit.edu>
Date: 23 Oct 90 16:01:16 GMT
References: <8660@ncar.ucar.edu> <2039@excelan.COM> <443@mole-end.UUCP>
Sender: daemon@athena.mit.edu (Mr Background)
Organization: Massachusetts Institute of Technology
Lines: 26

In article <443@mole-end.UUCP> mat@mole-end.UUCP (Mark A Terribile) writes:
>> >>Don't ever use single-character variable names.  I use 'ix' for
>> >>loop index variables for which I can come up with no better name...
>
>> >In what way is "ix" superior to "i"?  Both are meaningless names ...
>> >If the name is not going to be meaningful ... then at least keep it short.

Okay, I'll bite on this one.  First, a disclaimer that I usually use "i"
as a loop variable anyway.

"ix" is superior because "i" can sometimes be confused with "1",
depending on your printer.  This happened to a friend once:

int a[height][width];
for(i=0; i<height; i++)
  for(j=0; j<width; j++) 
    v = (a[i-1][j-1] + a[i][j-1] + a[i-1][j+i] +
         a[i-1][j] + a[i][j] + a[i-1][j+1] +
         a[i-1][j+1] + a[i][j-1] + a[i-1][j+1])/9;

y'all see the mistake at the end of line the 4th line immediately,
right?

using a 2-character loop variable makes this much less likely to happen.

-michael j zehr