Hi

I need to create a non-dynamic array like this

void f(int x)
{
int[x] my_array;
...

this does not compile as x value needs to be known at compile time. The closest to this I can get is:

void f(int x)
{
int[] my_array;
my_array.length=x;

but I don't really need a dynamic array as length is not going to change inside f.

What is the best way to do this?

Also what is it possible in D to write a function that accepts an static array of any size?

Thanks in advance

On Wednesday, 12 July 2017 at 05:45:13 UTC, Miguel L wrote:
> Hi
>
> I need to create a non-dynamic array like this
>
> void f(int x)
> {
> int[x] my_array;
> ...
>
> this does not compile as x value needs to be known at compile time. The closest to this I can get is:
>
> void f(int x)
> {
> int[] my_array;
> my_array.length=x;
>
> but I don't really need a dynamic array as length is not going to change inside f.
>
> What is the best way to do this?
>
> Also what is it possible in D to write a function that accepts an static array of any size?
>
> Thanks in advance

Sorry, this post is duplicated. Yesterday forum was not working and i received an error when i was trying to post it. Please ignore it.

On Wednesday, 12 July 2017 at 05:45:13 UTC, Miguel L wrote:
> void f(int x)
> {
> int[] my_array;
> my_array.length=x;
>
> but I don't really need a dynamic array as length is not going to change inside f.

Then just don't change the length... this is a correct way to do it.

You could also allocate it with `alloca` or `malloc` depending on exact use.

I also sometimes like to just slice a static array:

```
void f(int x) {
   int[1000] buffer;
   int[] my_array = x < buffer.length ? buffer[0 .. x] : new int[](x);
}
```

Which gives the speed benefits of static without putting a size limit on it.

Just make sure you keep track of ownership with any of these strategies.

> Also what is it possible in D to write a function that accepts an static array of any size?

Best option is to just accept a slice:

void f(int[] x);


and call it like so:

int[123] some_static_array;
f(some_static_array[]);


That will work on any size and typically give best performance. Again though, just use caution about ownership when using static arrays.

On Wednesday, 12 July 2017 at 05:45:13 UTC, Miguel L wrote:
> Also what is it possible in D to write a function that accepts an static array of any size?

void foo(size_t N)(ref int[N] arr) {
    ...
}

int[10] arr;
foo(arr);

On Wednesday, 12 July 2017 at 18:49:23 UTC, Jack Applegame wrote:
> On Wednesday, 12 July 2017 at 05:45:13 UTC, Miguel L wrote:
>> Also what is it possible in D to write a function that accepts an static array of any size?
>
> void foo(size_t N)(ref int[N] arr) {
>     ...
> }
>
> int[10] arr;
> foo(arr);

Thank you very much for your answers.