type
  TSuit = (Hearts, Clubs, Diamonds, Spades);
var
  Character : char;
  Number    : Integer;
  Card      : TSuit;

begin
  // Мы можем уменьшать символы
  Character := 'B';

  ShowMessage('Character : '+Character);
  Dec(Character);
  ShowMessage('Character-1 : '+Character);

  // Мы можем уменьшать числа
  Number := 23;

  ShowMessage('Number : '+IntToStr(Number));
  Dec(Number, 5);
  ShowMessage('Number-5 : '+IntToStr(Number));

  // Мы можем уменьшать перечисления
  Card := Clubs;

  ShowMessage('Card starts at Clubs');
  Dec(Card);
  if Card = Hearts then ShowMessage('Card is now Hearts');
  if Card = Clubs then ShowMessage('Card is now Clubs');
  if Card = Diamonds then ShowMessage('Card is now Diamonds');
  if Card = Spades then ShowMessage('Card is now Spades');
end;