Hello.
One question it is.
Why I cannot do something like this:

typedef int[] vint;
vint vector = new vint;   // [error]

?

join wrote:
> Hello.
> One question it is.
> Why I cannot do something like this:
> 
> typedef int[] vint;
> vint vector = new vint;   // [error]

int[] is a reference to an integer array. The REFERENCE does not have to be explicitly allocated.

If you want to allocate the ARRAY you must specify a size, otherwise it wouldn't be possible to determine the amount of memory it uses. For example:

int[] vint = new int[10];


Hauke

join wrote:

> Hello.
> One question it is.
> Why I cannot do something like this:
> 
> typedef int[] vint;
> vint vector = new vint;   // [error]

---------
typedef int[] vint;
vint* vector = new vint; // legal but rather pointless: you are allocating
                         // the space for one reference on the heap

vint vector = cast(vint)(new int[13]); // more useful but awkward

vint vector; vector.length = 13;  // This does the magic
---------

OK, people... BUT:

typedef int[] vint;
vint* vector = new vint;	// [ERROR]: new can only create structs, arrays or
class objects, not vint's

I made some type by _typedef_.
Now I’m going to allocate it somehow as other types.
How can I do it? Or can I do it anyway?


:-\
In article <cbunr7$ilh$1@digitaldaemon.com>, Norbert Nemec says...
>
>join wrote:
>
>> Hello.
>> One question it is.
>> Why I cannot do something like this:
>> 
>> typedef int[] vint;
>> vint vector = new vint;   // [error]
>
>---------
>typedef int[] vint;
>vint* vector = new vint; // legal but rather pointless: you are allocating
>                         // the space for one reference on the heap
>
>vint vector = cast(vint)(new int[13]); // more useful but awkward
>
>vint vector; vector.length = 13;  // This does the magic
>---------
>

the same error happens if you take out the typedef and just do:

int main() {
  int* vector = new int[];
  return 0;
}

so you see the key is you need to specify how big an array to allocate - not just that you want to allocate an array.

"join" <join_member@pathlink.com> wrote in message news:cbv2ja$120u$1@digitaldaemon.com...
> OK, people... BUT:
>
> typedef int[] vint;
> vint* vector = new vint; // [ERROR]: new can only create structs, arrays
or
> class objects, not vint's
>
> I made some type by _typedef_.
> Now I'm going to allocate it somehow as other types.
> How can I do it? Or can I do it anyway?
>
>
> :-\
> In article <cbunr7$ilh$1@digitaldaemon.com>, Norbert Nemec says...
> >
> >join wrote:
> >
> >> Hello.
> >> One question it is.
> >> Why I cannot do something like this:
> >>
> >> typedef int[] vint;
> >> vint vector = new vint;   // [error]
> >
> >---------
> >typedef int[] vint;
> >vint* vector = new vint; // legal but rather pointless: you are
allocating
> >                         // the space for one reference on the heap
> >
> >vint vector = cast(vint)(new int[13]); // more useful but awkward
> >
> >vint vector; vector.length = 13;  // This does the magic
> >---------
> >
>
>

But here:

int main ( char[][] args ) {

int[] vector1 = new int[256];  // done

typedef int[256] vint;         // specify the dimention vint* vector2 = new vint;      // [error]: what's wrong now?

return 0;
}

In article <cbv4bl$14om$1@digitaldaemon.com>, Ben Hinkle says...
>
>the same error happens if you take out the typedef and just do:
>
>int main() {
>  int* vector = new int[];
>  return 0;
>}
>
>so you see the key is you need to specify how big an array to allocate - not just that you want to allocate an array.

"join" <join_member@pathlink.com> wrote in message news:cbv93g$1bjg$1@digitaldaemon.com...
> But here:
>
> int main ( char[][] args ) {
>
> int[] vector1 = new int[256];  // done
>
> typedef int[256] vint;         // specify the dimention vint* vector2 = new vint;      // [error]: what's wrong now?

You cannot new a rectangular array an that is what vint is.
You can do:
 vint array;
 vint *vector2 = &array;

>
> return 0;
> }
>
> In article <cbv4bl$14om$1@digitaldaemon.com>, Ben Hinkle says...
> >
> >the same error happens if you take out the typedef and just do:
> >
> >int main() {
> >  int* vector = new int[];
> >  return 0;
> >}
> >
> >so you see the key is you need to specify how big an array to allocate -
not
> >just that you want to allocate an array.
>
>

On Wed, 30 Jun 2004 20:50:56 +0000 (UTC), join <join_member@pathlink.com> wrote:
> But here:
>
> int main ( char[][] args ) {
>
> int[] vector1 = new int[256];  // done
>
> typedef int[256] vint;         // specify the dimention
> vint* vector2 = new vint;      // [error]: what's wrong now?
>
> return 0;
> }

The trouble stems from int[] and int[256] being slightly different things, and the syntax used with each beig different also. int[] is a dynamic array, it can be resized etc. int[256] is a static array, it cannot be resized.

However, when you say 'new int[256]' you create a dynamic array (int[]) NOT a static array (int[256]).

You have two choices when allocating an array...

1. use a dynamic array like so:
  int[] a = new int[256];

2. use a static array like so:
  int[256] a;

both the above allocate an array of 256 int's. Given that, it does not seem possible to use a typedef as you have described, but, it also seems pointless to me.

You can go:

  typedef int[256] vint;
  vint a;

if you want vint to mean "a static array of length 256".

Regan

> In article <cbv4bl$14om$1@digitaldaemon.com>, Ben Hinkle says...
>>
>> the same error happens if you take out the typedef and just do:
>>
>> int main() {
>>  int* vector = new int[];
>>  return 0;
>> }
>>
>> so you see the key is you need to specify how big an array to allocate - not
>> just that you want to allocate an array.
>
>



-- 
Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/

I've got some bug in me... :)

int main (char[][] args) {

ubyte[256] vec1 = new ubyte[256];

alias ubyte[256] vec256;
vec256* vec2 = new vec256;

// [error]: new can only create structs, _arrays_ or class objects, not
ubyte[256]'s
// Is ubyte[256] not array? 8-)
// Can we make new array at runtime? :D

return 0;
}

In article <opsafftaxo5a2sq9@digitalmars.com>, Regan Heath says...
>
>On Wed, 30 Jun 2004 20:50:56 +0000 (UTC), join <join_member@pathlink.com> wrote:
>> But here:
>>
>> int main ( char[][] args ) {
>>
>> int[] vector1 = new int[256];  // done
>>
>> typedef int[256] vint;         // specify the dimention vint* vector2 = new vint;      // [error]: what's wrong now?
>>
>> return 0;
>> }
>
>The trouble stems from int[] and int[256] being slightly different things, and the syntax used with each beig different also. int[] is a dynamic array, it can be resized etc. int[256] is a static array, it cannot be resized.
>
>However, when you say 'new int[256]' you create a dynamic array (int[]) NOT a static array (int[256]).
>
>You have two choices when allocating an array...
>
>1. use a dynamic array like so:
>   int[] a = new int[256];
>
>2. use a static array like so:
>   int[256] a;
>
>both the above allocate an array of 256 int's. Given that, it does not seem possible to use a typedef as you have described, but, it also seems pointless to me.
>
>You can go:
>
>   typedef int[256] vint;
>   vint a;
>
>if you want vint to mean "a static array of length 256".
>
>Regan
>
>> In article <cbv4bl$14om$1@digitaldaemon.com>, Ben Hinkle says...
>>>
>>> the same error happens if you take out the typedef and just do:
>>>
>>> int main() {
>>>  int* vector = new int[];
>>>  return 0;
>>> }
>>>
>>> so you see the key is you need to specify how big an array to allocate
>>> - not
>>> just that you want to allocate an array.
>>
>>
>
>
>
>-- 
>Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/

On Wed, 30 Jun 2004 22:26:15 +0000 (UTC), join <join_member@pathlink.com> wrote:

> I've got some bug in me... :)

I found this too.. I think it might be a bug.
Both alias and typedef give similar tho slightly different errors.

However as Ivan mentions, your statement is still slightly wrong, you cannot go

alias ubyte[256] vec256;
vec256* vec2 = new vec256;

new vec256 returns an array reference, not a pointer, you have to go

alias ubyte[256] vec256;
ubyte[] tmp = new vec256;
vec256* vec2 = &tmp;

> int main (char[][] args) {
>
> ubyte[256] vec1 = new ubyte[256];
>
> alias ubyte[256] vec256;
> vec256* vec2 = new vec256;
>
> // [error]: new can only create structs, _arrays_ or class objects, not
> ubyte[256]'s
> // Is ubyte[256] not array? 8-)
> // Can we make new array at runtime? :D
>
> return 0;
> }
>
> In article <opsafftaxo5a2sq9@digitalmars.com>, Regan Heath says...
>>
>> On Wed, 30 Jun 2004 20:50:56 +0000 (UTC), join <join_member@pathlink.com>
>> wrote:
>>> But here:
>>>
>>> int main ( char[][] args ) {
>>>
>>> int[] vector1 = new int[256];  // done
>>>
>>> typedef int[256] vint;         // specify the dimention
>>> vint* vector2 = new vint;      // [error]: what's wrong now?
>>>
>>> return 0;
>>> }
>>
>> The trouble stems from int[] and int[256] being slightly different things,
>> and the syntax used with each beig different also. int[] is a dynamic
>> array, it can be resized etc. int[256] is a static array, it cannot be
>> resized.
>>
>> However, when you say 'new int[256]' you create a dynamic array (int[])
>> NOT a static array (int[256]).
>>
>> You have two choices when allocating an array...
>>
>> 1. use a dynamic array like so:
>>   int[] a = new int[256];
>>
>> 2. use a static array like so:
>>   int[256] a;
>>
>> both the above allocate an array of 256 int's. Given that, it does not
>> seem possible to use a typedef as you have described, but, it also seems
>> pointless to me.
>>
>> You can go:
>>
>>   typedef int[256] vint;
>>   vint a;
>>
>> if you want vint to mean "a static array of length 256".
>>
>> Regan
>>
>>> In article <cbv4bl$14om$1@digitaldaemon.com>, Ben Hinkle says...
>>>>
>>>> the same error happens if you take out the typedef and just do:
>>>>
>>>> int main() {
>>>>  int* vector = new int[];
>>>>  return 0;
>>>> }
>>>>
>>>> so you see the key is you need to specify how big an array to allocate
>>>> - not
>>>> just that you want to allocate an array.
>>>
>>>
>>
>>
>>
>> --
>> Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/
>
>



-- 
Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/