unit game;
{HiLo - a number guessing game conceptualised by wOnKo
 users try to guess a random number between 1 and 100
 They have 10 gos before the game is over}
interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TMainForm = class(TForm)
    play: TButton;
    done: TButton;
    tally: TLabel;
    procedure doneClick(Sender: TObject);
    procedure playClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  MainForm: TMainForm;

implementation

{$R *.DFM}

procedure TMainForm.doneClick(Sender: TObject);
begin
  close
end;

procedure TMainForm.playClick(Sender: TObject);
var  guess,                           {the number version of the users guess}
     mystery,                         {the random [1..100] invented for each game}
     numguesses,                      {the tally of the number of guesses}
     hi, lo          : integer;       {the high and low boundaries of guess range}
     reply,                           {user input}
     display         : string;        {for constructing output messages into}
begin
     {initialize}
     numguesses := 0;
     hi := 100; lo := 1;
     tally.caption := '10';
     {create the Mystery random number}
     mystery := random(100)+1;

     {play a round}
     repeat
        {construct bounded output range}
        display := 'Number between: '+inttostr(hi)+' and '+inttostr(lo);
        {prompt for a guess}
        reply := inputbox('Number Guesser',display,'');
        {safely acccept user input}
        guess := strTointDef(reply, -1);

        {process user input}
        if (guess = -1) or (guess > 100) or (guess < 1)
           then showmessage('Please enter a valid number')  {error trap}
           else if guess > mystery
                   then begin
                           showmessage('too high');
                           hi := guess
                        end
                   else if guess < mystery
                           then  begin
                                    showmessage('too low');
                                    lo := guess
                                 end
                           else  showmessage('yay - you got it!');
        inc(numguesses);
        tally.caption := inttostr(10-numguesses)
     until (numguesses = 10) or (mystery = guess); {game over}
     if  (numguesses = 10) and (mystery <> guess)
        then showmessage('Guesses exhausted - try again')

end;

procedure TMainForm.FormCreate(Sender: TObject);
begin
  randomize
end;

end.