Dear all,

I am trying to sort a simple TIntegerList defined as:

TIntegerList = specialize TFPGList<Integer>;

In order to sort I introduced a compare function as:

function CompareInt(const Item1,
   Item2: Integer): Integer;
begin
   if Item1 < Item2 then
     Result:= -1
   else if Item2 > Item1 then
     Result:= 1
   else
    Result:= 0;
end;
but I did not obtain the expected results.
Here a simple example:
procedure TForm1.Button1Click(Sender: TObject);
var
   i: Integer;
   il: TIntegerList;
begin
   il:= TIntegerList.Create;
   il.add(5);
   il.Add(3);
   il.add(8);
   il.Add(2);
   il.add(2);
   il.Add(1);
   ListBox1.Clear;
   for i:= 0 to il.Count - 1 do
     ListBox1.Items.Add(IntToStr(il[i]));
   il.Sort(@CompareInt);
   ListBox2.Clear;
   for i:= 0 to il.Count - 1 do
     ListBox2.Items.Add(IntToStr(il[i]));
   il.Free;
end;
Starting from a sequence of:
5,3,8,2,2,1
I got as sorted list:
2,2,1,3,5,8

What am I doing wrong?

Andrea

This is wrong. It is in fact the same condition as your first if. it should be

   if Item1>Item2 then

Michael.

As alternative you can use https://github.com/dathox/generics.collections (requires FPC 3.0).

You can use TList from Generics.Collections, is much simpler in usage:

======code begin======
type
  TIntegerList = specialize TList<Integer>;
procedure TForm1.Button1Click(Sender: TObject);
var
  i: Integer;
  il: TIntegerList;
begin
  il:= TIntegerList.Create;
  il.add(5);
  il.Add(3);
  il.add(8);
  il.Add(2);
  il.add(2);
  il.Add(1);
  ListBox1.Clear;
  for i:= 0 to il.Count - 1 do
    ListBox1.Items.Add(IntToStr(il[i]));
  il.Sort();
  ListBox2.Clear;
  for i:= 0 to il.Count - 1 do
    ListBox2.Items.Add(IntToStr(il[i]));
  il.Free;
end;
======code end======

Thanks and sorry for this stupid mistake.
Il 08/ott/2015 16:47, "Michael Van Canneyt" ha
scritto:

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