From: Martin Ambuhl <mambuhl AT earthlink DOT net>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: it's amazing (at least for me)
Date: Sun, 11 Jul 1999 01:46:47 -0400
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To: djgpp AT delorie DOT com
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aperes wrote:
> 
> In this little C program if i change the type of variable k (in setup
> function) to byte the program don't work. Can anyone explain me why?
> Thanks

The maximum value an unsigned char can hold is 255.  
unsigned char i = 255;
i++;
/* now i == 0 */

So i<256 is always true.



> 
> APeres.
> 
> ------------------------------------------------------------------------------------
> typedef  unsigned char  byte;
> typedef  unsigned char  pallette[256][3];
> 
> void setup(pallette);
> 
> int main(void)
> {
>    int i;
>    pallette pall;
> 
>    setup(pall);
> 
>    for(i=0; i < 256; i++)
>       printf("%d ------- %d\n", i, pall[i][0]);
> 
>    return 1;
> 
> }
> 
> void setup(pallette pall)
> {
>    int k;
> 
>       for(k=0; k < 256; k++)
>       pall[k][0] = pall[k][1] = pall[k][2] = i;
> }