I want to print the contents of Array!int

import std.stdio;
import std.container;

void pr(Array!int a) {
	foreach(i, v; a[]) {
		writeln("%4s: %s\n", i, v);
	}
}

But when I compile it by DMD 2.062 on Windows
it says:

testArray.d(5): Error: cannot infer argument types
(line 5 is at "foreach(i, v; a[]) {" )

What's wrong? how can I iterate the array?

Thanks, aki.

On Saturday, 27 June 2015 at 17:43:13 UTC, aki wrote:
> I want to print the contents of Array!int
>
> import std.stdio;
> import std.container;
>
> void pr(Array!int a) {
> 	foreach(i, v; a[]) {
> 		writeln("%4s: %s\n", i, v);
> 	}
> }
>
> But when I compile it by DMD 2.062 on Windows
> it says:
>
> testArray.d(5): Error: cannot infer argument types
> (line 5 is at "foreach(i, v; a[]) {" )
>
> What's wrong? how can I iterate the array?
>
> Thanks, aki.

size_t i;
foreach (v; a[])
  writeln("%s: %s", i++, v);

On 06/27/2015 10:43 AM, aki wrote:

> void pr(Array!int a) {
>      foreach(i, v; a[]) {

You are rightly assuming that the loop counter is available for all container types. Unfortunately, it is the case only for arrays.

Luckily, it is very easy to achieve it with std.algorithm.enumerate:

import std.stdio;
import std.container;
import std.range;

void pr(Array!int a) {
    foreach(i, v; a[].enumerate) {
        writeln("%4s: %s\n", i, v);
    }
}

void main()
{
    auto a = Array!int();
    pr(a);
}

Ali

On Saturday, 27 June 2015 at 18:32:10 UTC, Ali Çehreli wrote:
>
> Luckily, it is very easy to achieve it with std.range.enumerate:
>

FTFY

On Saturday, 27 June 2015 at 18:32:10 UTC, Ali Çehreli wrote:
> On 06/27/2015 10:43 AM, aki wrote:
> You are rightly assuming that the loop counter is available for all container types. Unfortunately, it is the case only for arrays.

Now I know. Thanks for it.
aki.

On Saturday, 27 June 2015 at 17:43:13 UTC, aki wrote:
> But when I compile it by DMD 2.062 on Windows
> it says:
>
> testArray.d(5): Error: cannot infer argument types
> (line 5 is at "foreach(i, v; a[]) {" )

2.062 is really ancient, we're about to release 2.068 soon. Consider upgrading, because there have been tons of bugfixes since your version.

On current DMD, the error message is slightly clearer:

"Error: cannot infer argument types, expected 1 argument, not 2"

On Sunday, 28 June 2015 at 10:16:47 UTC, Marc Schütz wrote:
> On Saturday, 27 June 2015 at 17:43:13 UTC, aki wrote:
>> But when I compile it by DMD 2.062 on Windows
>> it says:
>>
>> testArray.d(5): Error: cannot infer argument types
>> (line 5 is at "foreach(i, v; a[]) {" )
>
> 2.062 is really ancient, we're about to release 2.068 soon. Consider upgrading, because there have been tons of bugfixes since your version.
>
> On current DMD, the error message is slightly clearer:
>
> "Error: cannot infer argument types, expected 1 argument, not 2"

Ah, you answered my another question.
Even if I put all the types like foreach(size_t i, int v; a[])
he still said "cannot infer." I wonder why he need to infer?
Now I got it. I'm looking forward 2.068.
Aki.