abstract class and TList

[Dzandaa]

Hi everybody

I have for example

Code: Pascal  [Select][+][-]

1. type
2.  c1 = class
3. begin
4.  function f(f1: double): double;
5. end;
6.  
7. Tc1List = specialize TObjectList<c1>;  
8.  
9. // c2
10. type
11. c2 = class(c1)
12. Private
13.  _dl: double;
14.  
15. Public
16.  constructor Create(d1, d2: double);
17.  function f(f1: double): Boolean; override;
18.  
19.  property dl: double read _dl;
20. end;
21.  
22. // c3
23. type
24. c3 = class(c1)
25. Private
26.  _dl: double;
27.  
28. Public
29.  constructor Create(d1, d2, d3: double);
30.  function f(f1: double): Boolean; override;
31.  
32.  property dl: double read _dl;
33. end;
34.  
35. TcList = specialize TObjectList<c1>;  
36.  
37. implementation  
38.  
39. constructor c2.Create(d1, d2: Double);
40. begin
41.  inherited create;
42.  _dl := d1+d2;
43. end;
44.  
45. function c2.f(f1: double): Boolean;
46. begin
47.  if(_dl = f1) then return true
48.  else return false;
49. end;
50.  
51. constructor c3.Create(d1, d2, d3: Double);
52. begin
53.  inherited create;
54.  _dl := d1+d2+d3;
55. end;
56.  
57. function c3.f(f1: double): Boolean;
58. begin
59.  if(_dl = f1) then return true
60.  else return false;
61. end;
62.  
63. [code=pascal]

in a created Tc1List

is it possible in a loop to add elements in a loop and how (example welcome)

Thank you.

B->

[Thaddy]

This will fail on syntax, and a lot more....:

Code: Pascal  [Select][+][-]

1. type
2. class c1   // unless you use macro's this is not pascal
3. begin
4.  function f(f1: double): double;
5. end;

But it is possible. Add example later when I cleaned up your code.
[edit] cleaned up, do you mean this:

Code: Pascal  [Select][+][-]

1. {$mode objfpc}
2. uses generics.collections;
3. type
4.   c1 = class abstract
5.   Protected
6.     _dl: double;
7.   public
8.     function f(f1: double): boolean;virtual;abstract;
9.   property dl: double read _dl;
10.   end;
11.  
12. c2 = class(c1)
13. Public
14.   constructor Create(d1, d2: double);
15.   function f(f1: double): boolean; override;
16. end;
17.  
18. Tc2List = specialize TObjectList<c1>;  
19.  
20. constructor c2.Create(d1, d2: Double);
21. begin
22.  inherited create;
23.  _dl := d1+d2;
24. end;
25.  
26. function c2.f(f1: double): Boolean;
27. begin
28.  if(_dl = f1) then result := true
29.  else result := false;
30. end;
31. var
32.   Objectlist:Tc2List;
33.   i:integer;
34. begin
35.   ObjectList := Tc2List.Create;
36.   for i := 0 to 99 do
37.     Objectlist.add(c2.Create(random,random));
38.   for i := 0 to 99 do
39.     writeln(ObjectList[i].dl:2:2);
40.   Objectlist.free;
41. end.

Because that is Object Pascal and we can work from there.

Although this is working, what is the point?
There are so many mistakes in the question code.
I hope this helps you. Also with the l and 1.

[Dzandaa]

Hi,
@Thaddy:

Sorry for the mistakes, but I directly enter the code in the forum, not with the IDE.

I corrected it (also without testing)

my goal is to create a list of c1 objects that can be either c2 or c3

Is it possible?

In my real program, my list is filled with the same item address

[jamie]

Hi,
@Thaddy:

Sorry for the mistakes, but I directly enter the code in the forum, not with the IDE.

I corrected it (also without testing)

my goal is to create a list of c1 objects that can be either c2 or c3

Is it possible?

In my real program, my list is filled with the same item address

Yes its possible since your list will be expecting the C1 as the base class.
add your classes as you wish but then when you get ready to access them you can use some type check information.

If C1Object is C2 Then with C2(C1Object) do
  begin
    ......
  end;

the same with C3 and so on.

[Paolo]

TObjectList ?

[Thaddy]

Yes, TObjectList<T> from generics.collections because it can auto-free the objects it contains.