€€Listing 1. The CARDS unit from Tahoe 5.

Unit Cards;

const  faceDown  = 0;
       hearts    = 1;
       diamonds  = 2;
       clubs     = 3;
       spades    = 4;

type

{ Card object }
TCard = Object
  face : 0..13;
  suit : 0..4;
  procedure init;
  function val : integer;
  procedure setCard(f, s : integer);
  procedure setVal(v : integer);
end;

{ Card deck object for dealing cards }
TDeck = Object
  dealt : array [0..52] of boolean;
  procedure init;
  function nextCard : integer;
end;

implementation

{ Initialize a new card face down }
procedure TCard.Init;
begin
  face := faceDown;
  suit := faceDown;
end;

{ Return a numeric card value 1..52 or 0 for face down }
function TCard.val : integer;
begin
  if face = faceDown
  then
    val :=  faceDown
  else
    val := (suit - 1) * 13 + face;
end;

{ Set a particular card }
procedure TCard.setCard(f, s : integer);
begin
  face := f;
  suit := s;
end;Üj      ÜŒ
{ Set a particular card value }
procedure TCard.setval(v : integer);
var adj : integer;
begin
  face := (v mod 13);
  if face = 0  then
  begin
    face := 13;
    adj := 1;
  end
  else
    adj := 0;
  suit := (v div 13) + 1 - adj;
end;

{ Initialize a new shuffled deck so all cards exist }
procedure TDeck.Init;
begin
  randomize;
  fillchar(dealt, sizeOf(dealt), false);
end;

{ Draw the next card from the deck }
function TDeck.NextCard : integer;
var card : integer;
begin
 repeat
   card := random(51)+1;
 until not dealt[Card];
 dealt[Card] := true;
 nextCard := card;
end;

begin
end.