TPointerPointerArray.Arr

Provides indexed access Pointer values in the elements for the array.

Declaration

Source position: dynamicarray.pas line 51

Description

Arr is an indexed Pointer property which provides access to array elements by their ordinal column and row positions. Array is the default property for the class instance.

See also

Example

program tarrayexample;

{$mode objfpc}{$H+}

uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Classes,
  strings,
  DynamicArray;
  
type
  TArrayExampleClass = class
  private
    procedure doDestroyItem(Sender: Tobject; Col,Row: Integer;var Item: Pointer);
  end;

procedure TArrayExampleClass.doDestroyItem(Sender: Tobject; Col,Row: Integer;
  var Item: Pointer);
begin
  StrDispose(Item);
end;


var
  FCols: TPointerPointerArray;
  ex: TArrayExampleClass;

begin
  FCols := TPointerPointerArray.Create;
  ex    := TArrayExampleClass.Create;
  FCols.OnDestroyItem := @ex.doDestroyItem;

  FCols.SetLength(8,8);
  FCols.arr[0,0] := StrNew('string1');
  FCols.arr[4,7] := StrNew('string2');
  FCols.arr[4,3] := StrNew('string3');

  writeln('0,0:' + Pchar(FCols.arr[0,0]));
  writeln('4,7:' + Pchar(FCols.arr[4,7]));

  FCols.MoveColRow(True,4,5);
  writeln('after moving column 4 to 5');
  writeln('5,7:' + Pchar(FCols.arr[5,7]));
  writeln('before exchanging row 7 and 3:');
  writeln('5,3:' + Pchar(FCols.arr[5,3]));
  writeln('5,7:' + Pchar(FCols.arr[5,7]));

  FCols.ExchangeColRow(False,7,3);
  writeln('after exchanging row 7 and 3:');
  writeln('5,3:' + Pchar(FCols.arr[5,3]));
  writeln('5,7:' + Pchar(FCols.arr[5,7]));

  FCols.DeleteColRow(true,5);
  writeln('after deleting column 5:');

  try
    writeln('5,3:' + Pchar(FCols.arr[5,3])); //this raises an exception
  except
    writeln ('An exception has taken place be because 5,3 does not exist.');
  end;

  try
    writeln('5,7:' + Pchar(FCols.arr[5,7])); //this raises an exception
  except
    writeln ('An exception has taken place be because 5,7 does not exist.');
  end;

  FCols.Clear; writeln('after clear:');
  try
    writeln('4,7:' + Pchar(FCols.arr[4,7])); //this raises an exception
  except
    writeln ('An exception has taken place be because 4,7 does not exist.');
  end;

  FCols.Destroy;
  ex.Destroy;
  readln;
end.