From:	"John M. Aldrich" <fighteer AT cs DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Dynamic Allocation of Multidimensional Arrays
Date:	Thu, 03 Apr 1997 20:18:02 -0800
Organization:	Two pounds of chaos and a pinch of salt
Lines:	33
Message-ID:	<334480FA.22D9@cs.com>
References:	<33448D13 DOT 664 AT ucsu DOT Colorado DOT edu>
Reply-To:	fighteer AT cs DOT com
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To:	djgpp AT delorie DOT com
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William Heymann wrote:
> 
> I was wondering how do I make an multi-dimensional array that itilalizes
> at run time without knowing any of the parameters. What I am doing is I
> am using an array to keep track of objects on the screen so that my
> colision detection works. I am also using Allegro and would like to add
> in the function that allows the user to select what resolution to run
> the screen in. Since the array is screen resolution dependent I need a
> way to create the array at runtime using the the values I get from
> Allegro.
> 
> So how do I make a dynamic two dimensional array in C++?

In C, you can just dynamically allocate a linear block of memory and
index it just like you would the screen memory.  For example:

unsigned char *buffer;

buffer = calloc( sizeof(char) * SCREEN_WIDTH * SCREEN_HEIGHT );
...
buffer + x + SCREEN_WIDTH * y = pixel;
  -or-
buffer[x + SCREEN_WIDTH * y] = pixel;

When you're done with it, be sure to free the buffer.  I can't imagine
that you'd do things much differently iin C++.

-- 
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| John M. Aldrich, aka Fighteer I  |        fighteer AT cs DOT com         |
| Plan:  To find ANYONE willing to |   http://www.cs.com/fighteer   |
| play Descent 2 on DWANGO!        | Tagline: <this space for rent> |
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