Which style is better?

[³á³á³á³á]

#include <stdlib.h>
int *array;

I want to use malloc.

(1) array = malloc( sizeof( int ) * size );

or

(2) array = malloc( sizeof( *array ) * size );

My book use the (1) style, it has more clarity.
I think the (2) is better, because sometimes I have to change the type

of array, I just change the declaration of array, the malloc will get the

right size without change.

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¡þ plum.cs.nccu.edu.tw

[Andreas Kahari]

In article <48********@shepjeng.twbbs.org>, ³á³á³á³á wrote:

#include <stdlib.h>
int *array;

I want to use malloc.

(1) array = malloc( sizeof( int ) * size );
(2) array = malloc( sizeof( *array ) * size );

My book use the (1) style, it has more clarity.
I think the (2) is better, because sometimes I have to change the type
of array, I just change the declaration of array, the malloc will get the
right size without change.

Both alternatives are perfectly valid.

If you know you have to change the type of the object, then use
the second alternative, of course, that's why the syntax is
allowed.

If you know for sure that you won't, then use the first.

--
Andreas Kähäri

[Nathan]

> #include <stdlib.h>

int *array;

I want to use malloc.

(1) array = malloc( sizeof( int ) * size );

or

(2) array = malloc( sizeof( *array ) * size );

My book use the (1) style, it has more clarity.
I think the (2) is better, because sometimes I have to change the type

of array, I just change the declaration of array, the malloc will get the
right size without change.

A different solution could be to use a typedef to define the type of your
array.

Regards,
Nathan

[pete]

Andreas Kahari wrote:

In article <48********@shepjeng.twbbs.org>, ³á³á³á³á wrote:

#include <stdlib.h>
int *array;

I want to use malloc.

(1) array = malloc( sizeof( int ) * size );
(2) array = malloc( sizeof( *array ) * size );

My book use the (1) style, it has more clarity.
I think the (2) is better, because sometimes I have to change the type
of array, I just change the declaration of array, the malloc will get the
right size without change.

Both alternatives are perfectly valid.

If you know you have to change the type of the object, then use
the second alternative, of course, that's why the syntax is
allowed.

If you know for sure that you won't, then use the first.

I always use the second way,
without even thinking about it.

--
pete

[David Rubin]

Nathan wrote:

#include <stdlib.h>
int *array;

I want to use malloc.

(1) array = malloc( sizeof( int ) * size );

or

(2) array = malloc( sizeof( *array ) * size );

My book use the (1) style, it has more clarity.
I think the (2) is better, because sometimes I have to change the type

of array, I just change the declaration of array, the malloc will get

the

right size without change.

A different solution could be to use a typedef to define the type of your
array.

Different, but suboptimal. Always use the second form. That way, you
never have to worry about the type of array.

/david

--
Andre, a simple peasant, had only one thing on his mind as he crept
along the East wall: 'Andre, creep... Andre, creep... Andre, creep.'
-- unknown

[Richard Heathfield]

[unprintable] wrote:

#include <stdlib.h>
int *array;

I want to use malloc.

(1) array = malloc( sizeof( int ) * size );

or

(2) array = malloc( sizeof( *array ) * size );

My book use the (1) style, it has more clarity.
I disagree.
I think the (2) is better

I agree.

Case closed.

--
Richard Heathfield : bi****@eton.powernet.co.uk
"Usenet is a strange place." - Dennis M Ritchie, 29 July 1999.
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
K&R answers, C books, etc: http://users.powernet.co.uk/eton

[Artie Gold]

Richard Heathfield wrote:

[unprintable] wrote:

#include <stdlib.h>
int *array;

I want to use malloc.

(1) array = malloc( sizeof( int ) * size );

or

(2) array = malloc( sizeof( *array ) * size );

My book use the (1) style, it has more clarity.

I disagree.

I think the (2) is better

I agree.

Case closed.

But it would be better to write it as:

array = malloc( sizeof *array * size );

as the parentheses are not necessary when using the `sizeof'
operator on an object (as opposed to a fully parenthesized type).

HTH,
--ag
--
Artie Gold -- Austin, Texas

[Richard Heathfield]

Artie Gold wrote:

<snip>

But it would be better to write it as:

array = malloc( sizeof *array * size );

as the parentheses are not necessary when using the `sizeof'
operator on an object (as opposed to a fully parenthesized type).

Oh, absolutely. I only said (2) was better, not that it was perfect. :-)

(A review of my articles on the subject will, I think, bear this out.)

--
Richard Heathfield : bi****@eton.powernet.co.uk
"Usenet is a strange place." - Dennis M Ritchie, 29 July 1999.
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
K&R answers, C books, etc: http://users.powernet.co.uk/eton

[Artie Gold]

Richard Heathfield wrote:

Artie Gold wrote:

<snip>

But it would be better to write it as:

array = malloc( sizeof *array * size );

as the parentheses are not necessary when using the `sizeof'
operator on an object (as opposed to a fully parenthesized type).

Oh, absolutely. I only said (2) was better, not that it was perfect. :-)

(A review of my articles on the subject will, I think, bear this out.)

Of course. 'Twas posted for benefit of the OP.

--ag
--
Artie Gold -- Austin, Texas