access violation error

why? I dont think so becuase len:=high(ar)-low(ar);//if ar is [0,1,2,3,4,5] len is 5 and
I want actually to loop through all elements of this array from 0 to 5.

SetLength(CopyAr, Len);// the copy array's length is now less than the original's by one

Shouldn't that be

SetLength(CopyAr, N);// the copy array's length is now less than the original's by one

Is this what you're trying to do?

procedure ReduceArrayByNO(var Ar: TMyArray; NO: integer);
var
  I: Integer;
begin
  try
    for I := NO to Length(Ar) - 2 do
      Ar[I] := Ar[I + 1];

    SetLength(Ar, Length(Ar) - 1);
  except
  end;
end;

Paul thank, but actually i simplified the function to ask here. the function will take an array of cards and the card you want to exclude from the array. I approched this by first creating a copyarray whose length is less than the original by one. Then while filling the copyarray with items in the original, i put a condition that if the NO provided which is a card or a number in this example is equal to Ar[I] then ignore it and continue until finished. this way i am assured that we will not be outbounds. here is the code again with comments

type
  TMyArray = array of integer;

procedure ReduceArrayByNO(var Ar: TMyArray; NO: integer);//suppose Ar has 6 elements
var
  I, J, X, N: Integer;
  Len: Integer;
  CopyAr: TMyArray;//now this will hold 5 elements
begin
  try
    Len := high(Ar) - low(Ar);//this will be 5-0=5
    N := Len - 1;    //N=5-1=4
    SetLength(CopyAr, Len);// Len is 5 (5 elements)
    J := 0;
    X := 0;
    for I := 0 to Len do //0 to 5 that is looping through 6 elements of the original array
      begin
        if Ar[I] <> NO then //we will copy the elemnts of original Array to the copy array only if NO is excluded
          begin
            CopyAr[X] := Ar[J];**************************************
            J := J + 1;
            X := X + 1;
          end;
        if Ar[I] = NO then
          begin
            J := J + 1;
          end;
      end;
    SetLength(Ar, Len);//now we reset the original array which had 6 element to accept only 5 elements. Len is 5
    for I := 0 to N do //N for i=0 to 4 because we loop through 5 elements of the new original array and the copyarray
                             //both arrays hold 5 elements
      begin
        Ar[I] := CopyAr[I];
      end; // for
  finally
    SetLength(CopyAr, 0);
  end;
end;


thanks

http://www.geocities.com/oalawneh/ToSend.zip

the function is working fine and above is an example project.
I dont know what might be producing the access violation error as I could not reproduce the error while tracing with same parameters.

Ok thanks I think it something wrong with delphi environement.

Hi

Your problem is probably the declaration

I:Integer;


This is a very usualy declaration especially amongst people used to Visual Basic.

Likewise

x:Integer;

This is caused by I or X being globally delared within another unit (perhaps a VCL).

Due to bad memory management by Delphi this causes the problem you are seeing.

I had exactly the same problem myself and by simply changing the variable name to ICounter, the problem disappeared.

The long term solution is to use a different memory manager.  I use FastShareMem.pas myself and now have no such problems.  You can download free from http://www.torry.net/pages.php?id=228 .

This is an essential for any project in my opinion.....


But hey .... what do I know.......


Voodooman

thank you voodooman. This solved the problem but why dont we find something official about this topic in delphi help?
confused:)

Hi

well why do Microsoft only have 'features by design' and not bugs.  I remember when Visual Basic support was free getting faxed a 15 page workaround for a bug that they called a 'design feature'.

Borland, Microsoft and all don't admit to these things.

This took me all the day to figure out.  I work for myself so this was a day that I didn't get paid for.

I include FastShareMem in all my projects and have no problem since.

Don't forget to allocate the points......

Voodooman