Penney's game: Difference between revisions

</pre>

=={{header|Pascal}}==

<lang pascal>PROGRAM Penney;

TYPE

CoinToss = (heads, tails);

Sequence = array [1..3] of CoinToss;

Player = record

bet: Sequence;

score: integer;

end;

VAR

Human, Computer: Player;

Rounds, Count: integer;

Function TossCoin: CoinToss;

{ Returns heads or tails at random }

Begin

if random(2) = 1 then TossCoin := Heads

else TossCoin := tails

End;

Procedure PutToss(toss: CoinToss);

{ Outputs heads or tails as a letter }

Begin

if toss = heads then write('H')

else write('T')

End;

Function GetToss: CoinToss;

{ Reads H or T from the keyboard in either lettercase }

var c: char;

Begin

{ Keep reading characters until we get an appropriate letter }

repeat read(c) until c in ['H', 'h', 'T', 't'];

{ Interpret the letter }

if c in ['H', 'h'] then GetToss := heads

else GetToss := tails

End;

Procedure ShowSequence(tosses: Sequence);

{ Outputs three coin tosses at once }

Var

i: integer;

Begin

for i := 1 to 3 do PutToss(tosses[i])

End;

Procedure ReadSequence(var tosses: Sequence);

{ Accepts three coin tosses from the keyboard }

Var i: integer;

Begin

{ Get the 3 letters }

for i := 1 to 3 do tosses[i] := GetToss;

{ Ignore the rest of the line }

readln

End;

Function Optimum(opponent: Sequence): Sequence;

{ Generates the optimum sequence against an opponent }

Begin

case opponent[2] of

heads: Optimum[1] := tails;

tails: Optimum[1] := heads

end;

Optimum[2] := opponent[1];

Optimum[3] := opponent[2]

End;

Function RandomSequence: Sequence;

{ Generates three random coin tosses }

Var

i: integer;

Begin

for i := 1 to 3 do RandomSequence[i] := TossCoin

End;

Function Match(first, second: Sequence): Boolean;

{ Detects whether a sequence of tosses matches another }

Var

different: boolean;

i: integer;

Begin

different := false;

i := 1;

while (i <= 3) and not different do begin

if not (first[i] = second[i]) then different := true;

i := i + 1

end;

Match := not different

End;

Procedure PlayRound(var human, computer: Player);

{ Shows coin tosses and announces the winner }

Var

{ We only ever need to store the 3 most recent tosses in memory. }

tosses: Sequence;

Begin

{ Start with the first three tosses }

write('Tossing the coin: ');

tosses := RandomSequence;

ShowSequence(tosses);

{ Keep tossing the coin until there is a winner. }

while not (Match(human.bet, tosses) or Match(computer.bet, tosses)) do begin

tosses[1] := tosses[2];

tosses[2] := tosses[3];

tosses[3] := TossCoin;

PutToss(tosses[3])

end;

{ Update the winner's score and announce the winner }

writeln;

writeln;

if Match(human.bet, tosses) then begin

writeln('Congratulations! You won this round.');

human.score := human.score + 1;

writeln('Your new score is ', human.score, '.')

end

else begin

writeln('Yay, I won this round!');

computer.score := computer.score + 1;

writeln('My new score is ', computer.score, '.')

end

End;

{ Main Algorithm }

BEGIN

{ Welcome the player }

writeln('Welcome to Penney''s game!');

writeln;

write('How many rounds would you like to play? ');

readln(Rounds);

writeln;

writeln('Ok, let''s play ', Rounds, ' rounds.');

{ Start the game }

randomize;

Human.score := 0;

Computer.score := 0;

for Count := 1 to Rounds do begin

writeln;

writeln('*** Round #', Count, ' ***');

writeln;

{ Choose someone randomly to pick the first sequence }

if TossCoin = heads then begin

write('I''ll pick first this time.');

Computer.bet := RandomSequence;

write(' My sequence is ');

ShowSequence(Computer.bet);

writeln('.');

repeat

write('What sequence do you want? ');

ReadSequence(Human.bet);

if Match(Human.bet, Computer.bet) then

writeln('Hey, that''s my sequence! Think for yourself!')

until not Match(Human.bet, Computer.bet);

ShowSequence(Human.bet);

writeln(', huh? Sounds ok to me.')

end

else begin

write('You pick first this time. Enter 3 letters H or T: ');

ReadSequence(Human.bet);

Computer.bet := Optimum(Human.bet);

write('Ok, so you picked ');

ShowSequence(Human.bet);

writeln;

write('My sequence will be ');

ShowSequence(Computer.bet);

writeln

end;

{ Then we can actually play the round }

writeln('Let''s go!');

writeln;

PlayRound(Human, Computer);

writeln;

writeln('Press ENTER to go on...');

readln

end;

{ All the rounds are finished; time to decide who won }

writeln;

writeln('*** End Result ***');

writeln;

if Human.score > Computer.score then writeln('Congratulations! You won!')

else if Computer.score > Human.score then writeln('Hooray! I won')

else writeln('Cool, we tied.');

writeln;

writeln('Press ENTER to finish.');

readln

END.</lang>

{{out}}

<pre>Welcome to Penney's game!

How many rounds would you like to play? 3

Ok, let's play 3 rounds.

*** Round #1 ***

I'll pick first this time. My sequence is TTH.

What sequence do you want? H tt

HTT, huh? Sounds ok to me.

Let's go!

Tossing the coin: HHHHTHHHHHHTHHHHTHHTHTHTT

Congratulations! You won this round.

Your new score is 1.

Press ENTER to go on...

*** Round #2 ***

I'll pick first this time. My sequence is THT.

What sequence do you want? tth

TTH, huh? Sounds ok to me.

Let's go!

Tossing the coin: THT

Yay, I won this round!

My new score is 1.

Press ENTER to go on...

*** Round #3 ***

You pick first this time. Enter 3 letters H or T: h t h

Ok, so you picked HTH

My sequence will be HHT

Let's go!

Tossing the coin: HHT

Yay, I won this round!

My new score is 2.

Press ENTER to go on...

*** End Result ***

Hooray! I won

Press ENTER to finish.