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Newsgroups: comp.lang.ada
Subject: Surprising behaviour of strings.fixed.overwrite
Date: Wed, 12 Nov 2014 11:49:29 +0100
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Date: 2014-11-12T11:49:29+01:00
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Given the following Ada program:

---%<---
with TEXT_IO;
with ADA.STRINGS;
with ADA.STRINGS.FIXED;

procedure TEST
is
    S : STRING(1 .. 6);
begin
    S := "@@@@@@";
    ADA.STRINGS.FIXED.OVERWRITE (S, S'First + 5, "56", ADA.STRINGS.LEFT);
    TEXT_IO.PUT_LINE (S);

    S := "@@@@@@";
    ADA.STRINGS.FIXED.OVERWRITE (S, S'First + 5, "56", ADA.STRINGS.RIGHT);
    TEXT_IO.PUT_LINE (S);
end;
--->%---

What would you expect to be the output of the program?

Scroll down for the answer...

















































Well, I would have expected the output to be

@@@@@6
@@@@@5

But it is:

@@@@56
@@@@@5

Which is correct according to the definition of overwrite, but nevertheless I 
find this extremely surprising.

Am I alone in this?

Or can anyone please the rational on defining the behaviour of overwrite as it is?

Markus