On Thursday, 20 February 2014 at 17:24:55 UTC, D Apprentice wrote:
Greetings, D wizards.
Given a static array, int[5] a, presumed to be filled with
random
numbers, how does one sort it using std.algorithm.sort? Calling
sort(a) by itself errors out with:
test.d(7): Error: template std.algorithm.sort does not match any
function template declaration. Candidates are:
/usr/share/dmd/src/phobos/std/algorithm.d(8387):
std.algorithm.sort(alias less = "a < b", SwapStrategy ss =
SwapStrategy.unstable, Range)(Range r) if ((ss ==
SwapStrategy.unstable && (hasSwappableElements!Range ||
hasAssignableElements!Range) || ss != SwapStrategy.unstable &&
hasAssignableElements!Range) && isRandomAccessRange!Range &&
hasSlicing!Range && hasLength!Range)
test.d(7): Error: template std.algorithm.sort(alias less = "a <
b", SwapStrategy ss = SwapStrategy.unstable, Range)(Range r) if
((ss == SwapStrategy.unstable && (hasSwappableElements!Range ||
hasAssignableElements!Range) || ss != SwapStrategy.unstable &&
hasAssignableElements!Range) && isRandomAccessRange!Range &&
hasSlicing!Range && hasLength!Range) cannot deduce template
function from argument types !()(int[5])
This is a general interest question. As I understand it, D
static
arrays are value types, as opposed to their dynamic siblings
which are reference types, and I suspect that is the underlying
issue here.
One little idiom I found, though I do not know if it's very
efficient, is using the array slice syntax:
sort (a[0..a.length]);
This works, but I'm curious if there's another (better) way? The
biggest advantage that I can see to the slice syntax is that it
allows the programmer to sort only part of the array, which one
could do in C with qsort.
Source:
import std.stdio;
import std.algorithm;
void main ()
{
int[5] a = [9, 5, 1, 7, 3];
//sort (a); //Fails
//sort (a[0..a.length]); //Works
writeln (a);
}
Thank you for your time.
static arrays are not slices. Using [] gives you a slice from a
static array. I often find myself writing this:
int[5] aStatic = [9, 5, 1, 7, 3];
auto a = aStatic[];
and just being careful not to leak references.
