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<div class="moz-cite-prefix">Hi,<br>
<br>
Leaving aside the reason why the MiSchi's solution doesn't work
the main question is still not answered :)<br>
<br>
If you have integer dynamic array "MyArray" is there a way for the
following statement to compile and work correctly:<br>
<br>
MyArray := 5;<br>
<br>
Thanks,<br>
Gennady<br>
<br>
<br>
On 11/3/2018 4:14 PM, Ben Grasset wrote:<br>
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cite="mid:CAL4d7FjcrC79t4AFVP7FZJxG3GaGB-hn2q0aJguzc5t0tbHCXA@mail.gmail.com">
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<div>On Sat, Nov 3, 2018 at 8:01 AM Schindler Karl-Michael
<<a href="mailto:karl-michael.schindler@web.de"
moz-do-not-send="true">karl-michael.schindler@web.de</a>>
wrote:<br>
</div>
</div>
</div>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">Hi<br>
<br>
I would like to use a simple assignment operator for arrays,
with which all elements of an array are assigned to the same
value, similar to an extended initialize, not to zero but to
a value of choice. A simple example for an integer array
would be:<br>
<br>
myArray := 5;<br>
<br>
With arrays with defined bounds, it works, but i was not
able to do it with a dynamic array. My test case is this:<br>
<br>
program arrayAssign;<br>
<br>
type<br>
TmyArray = array of integer;<br>
<br>
var<br>
myArray: TmyArray;<br>
index: integer;<br>
<br>
operator := (const number: integer) theResult: TmyArray;<br>
var<br>
i: integer;<br>
begin<br>
for i := low(theResult) to high(theResult) do<br>
theResult[i] := number;<br>
end;<br>
<br>
begin<br>
setlength(myArray, 10);<br>
writeln ('myArray: ', low(myArray), ', ', high(myArray));<br>
<br>
myArray := 5;<br>
<br>
writeln ('myArray: ', low(myArray), ', ', high(myArray));<br>
for index := low(myArray) to high(myArray) do<br>
writeln (index, ': ', myArray[index]);<br>
end.<br>
<br>
The output is:<br>
<br>
myArray: 0, 9<br>
myArray: 0, -1<br>
<br>
The problem is that in the declaration of the operator, the
functions low and high seem to return the values of the type
TmyArray, i.e. 0 and -1 and not the values of the variable
of the assignment statement, i.e. myArray and the assignment
nullifies the previous setlength. Is there any way around
this and obtain the actual values of myArray?<br>
<br>
Michael, aka MiSchi.<br>
_______________________________________________<br>
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href="mailto:fpc-devel@lists.freepascal.org"
target="_blank" moz-do-not-send="true">fpc-devel@lists.freepascal.org</a><br>
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<div><br>
</div>
There's two issues:
<div>1) The result of the operator is always a new, unique
array (as in it's unrelated to the myArray variable)</div>
<div>2) Your operator doesn't initialize the result with a
length, so it's just iterating over nothing.</div>
<div><br>
</div>
<div>Here's an example of the correct way to write the
operator and use it:</div>
<div><br>
</div>
<div>
<div>program ArrayOverloads;</div>
<div><br>
</div>
<div>{$mode ObjFPC}</div>
<div><br>
</div>
<div>type TIntArray = array of Integer;</div>
<div><br>
</div>
<div> operator := (const I: Integer): TIntArray; inline;</div>
<div> var V: Integer;</div>
<div> begin</div>
<div> SetLength(Result, I);</div>
<div> for V := 0 to Pred(I) do Result[V] := V;</div>
<div> end;</div>
<div><br>
</div>
<div>var</div>
<div> I: Integer;</div>
<div> IA: TIntArray;</div>
<div><br>
</div>
<div>begin</div>
<div> IA := 25;</div>
<div> for I in IA do Write(I, ' ');</div>
<div> WriteLn;</div>
<div> for I := High(IA) downto 0 do Write(I, ' ');</div>
<div> WriteLn;</div>
<div> for I := Low(IA) to High(IA) do Write(I, ' ');</div>
<div> WriteLn;</div>
<div> I := 0;</div>
<div> while I < Pred(High(IA)) do begin</div>
<div> Inc(I, 2);</div>
<div> Write(I, ' ');</div>
<div> end;</div>
<div>end.</div>
</div>
<div><br>
</div>
<div>Output:</div>
<div><br>
</div>
<div>
<div>0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
22 23 24</div>
<div>24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5
4 3 2 1 0</div>
<div>0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
22 23 24</div>
</div>
<div>2 4 6 8 10 12 14 16 18 20 22 24 <br>
</div>
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<pre wrap="">_______________________________________________
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</pre>
</blockquote>
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