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From: kevin@crash.cts.com (Kevin Hill)
Newsgroups: comp.sys.mac.programmer
Subject: For Loops, Summary
Message-ID: <6968@crash.cts.com>
Date: 16 Jan 91 08:50:53 GMT
Sender: root@crash.cts.com
Lines: 43


  I was pleasantly surprised today, Wednesday Morning 1:10am, to find my 
mailbox, full of letters telling me that I forgot to initialize 'i' in the 
code that I posted earlier.  However, I do assure you, that I was initialized...

I finally gave up and defined the 8 positions of surround by typing each case
out.  Oh, well.  Also, many Kudo's to Tom Shores who told me to get rid of
the blob of programming I had, and use the following
if ((gx+k<0)||(gx+k>GXMAX)||(gy-j<0)||(gy-j>GYMAX))
        surround[i] = -1;
  Wheeeew,  I didn't know I could smash all my code into that two line 
peice of if for loop!  Yowzers inspector gadget!
  I'll have to call on Tom to omptimize my program that I am writing for
me!
  Thanks to everyone who wrote, if you know of any bugs in Think C 3.01p4,
that involve for loops, please tell me because the problem that I am having, 
is something that should not happen.
 Also, all the variables, are initialized and surround is defined as a
int surround[9]; variable.  here's the code again, for those who missed it
>
>       for(j = -1;j < 2;j++)
>       {
>
>               for(k = -1;k < 2;k++)
>               {
>                       printf("%3d %3d\t",j,k);
>                       i++;
>                       surround[i] = track[gx+k][gy+j];
>                       if ( (gx+k) < 0)
>                               surround[i] = -1;
>                       if ( (gx+k) > GXMAX)
>                               surround[i] = -1;
>                       if ( (gy-j) < 0)
>                               surround[i] = -1;
>                       if ( (gy-j) > GYMAX)
>                               surround[i] = -1;
>               }
>
>       }

  The problem seems to be that the variables j and k do wild things after they
do what is expected of them.  Then they go off to change the correct value
of surround[9] to something wierd and go off into lala land.