From: "M. Darland" <mtd5922 AT omega DOT uta DOT edu>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: For loop problem
Date: Mon, 6 Apr 1998 10:18:40 -0500
Organization: University of Texas at Arlington
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Message-ID: <Pine.OSF.3.96.980406100657.26920B-100000@omega.uta.edu>
References: <3527FEA6 DOT 54FA AT vegas DOT infi DOT net>
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To: djgpp AT delorie DOT com
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On Sun, 5 Apr 1998, Simz wrote:

> When ever I try to use a for loop in DJGPP with a char (or any type for
> that matter), the loop never stops when I try to loop to the max value
> that type can hold. For example
> 
> unsigned char index = 0;
> unsigned char array[256];
> for (index = 0; index < 256; index++)
> 	array[index] = index;
> 
> This loop never stops, I've even tried..
> for (index = 0; index <= 255; index++)
> for (index = 0; index < 256; ++index)
> for (index = 0; index <= 255; ++index)
> 
> And I need all 256 iterations for my programs to work.
> Any sugestions?
> 
> Simz
> tsim AT vegas DOT infi DOT net
> 
> 
    Since unsigned char can only hold values from 0-255, when the loop
reaches 255 and increments, it 'increments' to 0. Not 256. So the
condition to stop at >255 will never occur. i.e. here is
the binary representation of 255( using unsigned char format), 11111111.
Add 1 and you get 00000000. The for loop is going from 0->255,0->255...
    The solution: use an unsigned short int( or larger ) instead.