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From: Martin Ambuhl <mambuhl AT earthlink DOT net>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Trouble of using very large arrays
Date: Fri, 23 Apr 2004 20:08:38 -0400
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Alex Vinokur wrote:

> "Martin Ambuhl" <mambuhl AT earthlink DOT net> wrote in message news:c6bafb$a9mhn$2 AT ID-227552 DOT news DOT uni-berlin DOT de...
> 
>>Cesar Rabak wrote:
>>
>>
>>>Brian Inglis escreveu:
>>
>>> > this is cleaner and more maintainable:
>>> >
>>> > a = malloc(rows * columns * sizeof *a);
>>> >
>>>This is not a good advice: you're changing the allocation of an object
>>>of (rows x columns) ints to another of (rows x columns) pointers to int.
>>
>>You are, I regret to say, in error.  The type of *a is int, not
>>pointers-to-int.
>>
> 
> 
> You are right. So,
>  a = malloc(rows * columns * sizeof  a);

Huh?  Why change the correct
    a = malloc(rows * columns * sizeof *a);
to something that's wrong?

The fact is that
   ptr = malloc(number * sizeof *ptr);
is the accepted, common C idiom here, no matter what the type of ptr. 
That's the point.