Hello,

I've been trying to implement a class for sorting which accepts arrays which "different" data types. Hard to describe, here's my example (filename sorting.d):

[code]
import std.random;

void main()
{
    immutable uint N = 10_000;

    double[] arr = new double[](N);
    for (uint k = 0; k < N; k++) arr[k] = uniform(0, N);

    BubbleSort b = new BubbleSort();
    b.Sort(arr);
}

public class BubbleSort(T)
{
    private T[] a;
    private uint n;

    public void Sort(T)(T[] a) {
        this.a = a;
        n = a.length;
        bubblesort();
    }

    private void bubblesort() {
        bool sorted;

        do {
            sorted = true;
            for (uint k = 0; k < n; k++) {
                if (a[k] > a[k+1]) {
                    T tmp = a[k];
                    a[k] = a[k+1];
                    a[k+1] = tmp;
                    sorted = false;
                }
            }
            n--;
        } while (!sorted);
    }
}
[/code]

Whenever I try to compile this, it throws an error "class sorting.BubbleSort(T) is used as a type". How do I get a workaround?

On Monday, 31 October 2016 at 19:24:46 UTC, Hefferman wrote:
> Whenever I try to compile this, it throws an error "class sorting.BubbleSort(T) is used as a type". How do I get a workaround?

Give a template type when crating it

new BubbleSort!(string)

for example

On Monday, 31 October 2016 at 19:43:57 UTC, Adam D. Ruppe wrote:
> On Monday, 31 October 2016 at 19:24:46 UTC, Hefferman wrote:
>
> Give a template type when crating it
>
> new BubbleSort!(string)
>
> for example

Is it possible to create this using "typeof"?
E. g. "BubbleSort b = new BubbleSort!(typeof(arr));"
Compilation fails with that line....

On Monday, 31 October 2016 at 20:06:22 UTC, Hefferman wrote:
> On Monday, 31 October 2016 at 19:43:57 UTC, Adam D. Ruppe wrote:
>> On Monday, 31 October 2016 at 19:24:46 UTC, Hefferman wrote:
>>
>> Give a template type when crating it
>>
>> new BubbleSort!(string)
>>
>> for example
>
> Is it possible to create this using "typeof"?
> E. g. "BubbleSort b = new BubbleSort!(typeof(arr));"
> Compilation fails with that line....

You can't use an un-instantiated template as a type anyway, unlike Java. There the above is illegal because of `BubbleSort b = ...`. The symbol BubbleSort by itself is not a type; you have to instantiate it with template arguments to create a type. So you *could* do it like this:

BubbleSort!(typeof(arr)) b = new BubbleSort!(typeof(arr));

But that's too verbose. There's need need to repeat ourselves. You can instead use `auto` and omit the type of `b`, which will be inferred from the right hand side:

auto b = new BubbleSort!(typeof(arr));

On Monday, 31 October 2016 at 20:20:09 UTC, Meta wrote:
> [...]
>
> You can't use an un-instantiated template as a type anyway, unlike Java. There the above is illegal because of `BubbleSort b = ...`. The symbol BubbleSort by itself is not a type; you have to instantiate it with template arguments to create a type. So you *could* do it like this:
>
> BubbleSort!(typeof(arr)) b = new BubbleSort!(typeof(arr));
>
> But that's too verbose. There's need need to repeat ourselves. You can instead use `auto` and omit the type of `b`, which will be inferred from the right hand side:
>
> auto b = new BubbleSort!(typeof(arr));

Thanks! This compiled just fine...

[code]
import std.random;
import std.stdio;

void main()
{
    immutable uint N = 10_000;

    double[] arr = new double[](N);
    for (uint k = 0; k < N; k++) arr[k] = uniform(0, N);

    auto b = new BubbleSort!(typeof(arr));
    b.Sort(arr);
}

public class BubbleSort(T)
{
    private T[] a;
    private uint n;

    public void Sort(T)(T[] a) {
        n = a.length;
        bubblesort();
    }

    private void bubblesort() {
        bool sorted;

        do {
            sorted = true;
            for (uint k = 1; k < n; k++) {
                if (a[k-1] > a[k]) {
                    T tmp = a[k];
                    a[k] = a[k+1];
                    a[k+1] = tmp;
                    sorted = false;
                }
            }
            n--;
        } while (!sorted);
    }
}
[/code]

It gives a Range Violation upon executing, but I guess it's part of the algorithm....

On Monday, 31 October 2016 at 20:25:18 UTC, Hefferman wrote:
>             for (uint k = 1; k < n; k++) {
>                 if (a[k-1] > a[k]) {
>                     T tmp = a[k];
>                     a[k] = a[k+1];
>                     a[k+1] = tmp;
>                     sorted = false;
>                 }
>             }
>             n--;
>         } while (!sorted);
>     }
> }
> [/code]
>
> It gives a Range Violation upon executing, but I guess it's part of the algorithm....

The value of n is array length, so k reaches (n - 1), therefore k+1 gives you n which is out of bounds.

On Monday, 31 October 2016 at 19:24:46 UTC, Hefferman wrote:
> Hello,
>
> I've been trying to implement a class for sorting which accepts arrays which "different" data types. Hard to describe, here's my example (filename sorting.d):
>
> [...]

Glad to see you're getting helpful responses here, but just an FYI: https://forum.dlang.org/group/learn would be a more appropriate forum for questions like this.

On Monday, 31 October 2016 at 22:33:11 UTC, John Colvin wrote:
> On Monday, 31 October 2016 at 19:24:46 UTC, Hefferman wrote:
>> Hello,
>>
>> I've been trying to implement a class for sorting which accepts arrays which "different" data types. Hard to describe, here's my example (filename sorting.d):
>>
>> [...]
>
> Glad to see you're getting helpful responses here, but just an FYI: https://forum.dlang.org/group/learn would be a more appropriate forum for questions like this.

Thanks to all for replying!

@J.C.: I'll keep it in mind for the next time.