先定义一个函数：

private
    function weekday(WDays:Integer):string;

看实现部分的代码：

function TForm1.weekday(WDays: Integer): string;
type
  Tweek=(sunday,monday,tuesday,wednesday,thursday,friday,saturday);
var
  Days,NextDay:Tweek;
begin
  case WDays of
    0:Days:=sunday;
    1:Days:=monday;
    2:Days:=tuesday;
    3:Days:=wednesday;
    4:Days:=thursday;
    5:Days:=friday;
    6:Days:=saturday;
  end;
  if Days=saturday then
    NextDay:=sunday
  else
    NextDay:=succ(Days);
  case NextDay of
    sunday:Result:='sunday';
    monday:Result:='monday';
    tuesday:Result:='tuesday';
    wednesday:Result:='wednesday';
    thursday:Result:='thursday';
    friday:Result:='friday';
    saturday:Result:='saturday';

  end;
  Result:='明天是'+Result+' 呀！' ;
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
  ShowMessage(weekday(StrToInt(InputBox('輸入提示框','請輸入0~6之間的任一數字： ','0'))));
end;

procedure TForm1.Button5Click(Sender: TObject);
type chars='A'..'Z';
     ints=0..9;
var
  k1,k2,k3,k4:chars;
  k5,sum:Integer;
begin
  sum:=0;
  for k1:='A'to 'Z' do
    for k2:='A'to 'Z'do
      for k3:='A'to 'Z' do
        for k4:='A' to 'Z' do
          for k5:=0 to 9 do
            sum:=sum+1;
  ShowMessage(IntToStr(sum));//4569760
end;