From: "gautier...@hotmail.com" <gautier_niouzes@hotmail.com>
Subject: Re: advent of code day 11
Date: Fri, 11 Dec 2020 11:29:56 -0800 (PST) [thread overview]
Message-ID: <eb14771e-910b-4ad7-bad9-00928a4eb10fn@googlegroups.com> (raw)
In-Reply-To: <b4611f34-d553-4f7c-806a-c799cad8cc0bn@googlegroups.com>
> Perform_Round( Source => Source , Result => Result , ... );
> declare Tmp: Chart_Array renames Source;
> begin
> Source := Result;
> Result := Tmp;
> end;
To complete Jeff's answer, what you are doing is not a swap: it's equivalent to
Source := Result;
Result := Source;
Ooops.
The ":=" makes a complete copy of the arrays.
So you'd need above "Tmp : Chart_Array := Source" to have a correct swap with 3 copies.
Of course it feels a bit heavy to make all those copies. And you understandably want to avoid playing with pointers. So a solution is to define:
Map : array (0 .. 1) of Chart_Array;
...
current := 0;
loop
next := 1 - current;
Perform_Round( Source => Map (current), Result => Map (next) , ... );
current := next;
end loop;
next prev parent reply other threads:[~2020-12-11 19:29 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-11 17:07 advent of code day 11 Stephen Leake
2020-12-11 18:24 ` John Perry
2020-12-11 19:07 ` Jeffrey R. Carter
2020-12-11 19:29 ` gautier...@hotmail.com [this message]
2020-12-11 19:35 ` gautier...@hotmail.com
2020-12-11 22:40 ` Jeffrey R. Carter
2020-12-11 23:45 ` John Perry
2020-12-11 23:49 ` John Perry
2020-12-12 9:38 ` Maxim Reznik
2020-12-12 20:27 ` Stephen Leake
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