digitalmars.D - Classes and templates
- Hefferman (43/43) Oct 31 2016 Hello,
- Adam D. Ruppe (4/7) Oct 31 2016 Give a template type when crating it
- Hefferman (4/8) Oct 31 2016 Is it possible to create this using "typeof"?
- John Colvin (4/9) Oct 31 2016 Glad to see you're getting helpful responses here, but just an
- Hefferman (3/14) Nov 01 2016 Thanks to all for replying!
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?
Oct 31 2016
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
Oct 31 2016
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 exampleIs it possible to create this using "typeof"? E. g. "BubbleSort b = new BubbleSort!(typeof(arr));" Compilation fails with that line....
Oct 31 2016
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: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 19:24:46 UTC, Hefferman wrote: Give a template type when crating it new BubbleSort!(string) for exampleIs it possible to create this using "typeof"? E. g. "BubbleSort b = new BubbleSort!(typeof(arr));" Compilation fails with that line....
Oct 31 2016
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....
Oct 31 2016
Kapps <opantm2+spam gmail.com>
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.
Oct 31 2016
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.
Oct 31 2016
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:Thanks to all for replying! J.C.: I'll keep it in mind for the next time.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.
Nov 01 2016