21 game
You are encouraged to solve this task according to the task description, using any language you may know.
21 is a two player game, the game is played by choosing a number (1, 2, or 3) to be added to the running total. The game is won by the player whose chosen number causes the running total to reach exactly 21.
The running total starts at zero.
One player will be the computer.
Players alternate supplying a number to be added to the running total.
- Task
Write a computer program that will:
- do the prompting (or provide a button menu),
- check for errors and display appropriate error messages,
- do the additions (add a chosen number to the running total),
- display the running total,
- provide a mechanism for the player to quit/exit/halt/stop/close the program,
- issue a notification when there is a winner, and
- determine who goes first (maybe a random or user choice, or can be specified when the game begins).
AutoHotkey
<lang AutoHotkey>Gui, font, S16 Gui, add, Radio, vRadioC , Cake Gui, add, Radio, vRadioE x+0 Checked, Easy Gui, add, Radio, vRadioH x+0, Hard Gui, add, text, xs vT, Total : 00 Gui, add, text, xs vComputer, Computer Dealt 00 Gui, add, text, xs Section, Player 1 loop, 3 Gui, add, button, x+5 vPlayer1_%A_Index% gTotal, % A_Index Gui, add, button, xs vReset gReset, reset Gui show,, 21 Game Winners := [1,5,9,13,17,21] gosub, reset return
- -----------------------------------
reset: total := 0 GuiControl,, T, % "Total : " SubStr("00" Total, -1) GuiControl,, Computer, % "Computer Waiting" Loop 3 GuiControl, Enable, % "Player1_" A_Index Random, rnd, 0, 1 if rnd { Loop 3 GuiControl, Disable, % "Player1_" A_Index gosub ComputerTurn } return
- -----------------------------------
Total: Added := SubStr(A_GuiControl, 9,1) Total += Added GuiControl,, T, % "Total : " SubStr("00" Total, -1) if (total >= 21) { MsgBox % "Player 1 Wins" gosub reset return } Loop 3 GuiControl, Disable, % "Player1_" A_Index gosub, ComputerTurn return
- -----------------------------------
ComputerTurn: Gui, Submit, NoHide Sleep 500 if RadioE { if (total < 13) RadioC := true else RadioH := true } if RadioC { Random, Deal, 1, 3 total += Deal } if RadioH { for i, v in Winners if (total >= v) continue else { Deal := v - total if Deal > 3 Random, Deal, 1, 3 total += Deal break } } GuiControl,, T, % "Total : " SubStr("00" Total, -1) GuiControl,, Computer, % "Computer Dealt " Deal if (total=21) { MsgBox Computer Wins gosub, reset } else Loop 3 GuiControl, Enable, % "Player1_" A_Index return</lang>
awk
<lang awk># Game 21 - an example in AWK language for Rosseta Code.
BEGIN {
srand(); GOAL = 21; best[0] = 1; best[1] = 1; best[2] = 3; best[3] = 2;
print\
"21 Game \n"\
" \n"\
"21 is a two player game, the game is played by choosing a number \n"\
"(1, 2, or 3) to be added to the running total. The game is won by\n"\
"the player whose chosen number causes the running total to reach \n"\
"exactly 21. The running total starts at zero. \n\n";
newgame(); prompt();
}
/[123]/ {
move = strtonum($0);
if (move + total <= GOAL) {
update("human", strtonum($0));
update("ai", best[total % 4]);
}
else
invalid();
prompt();
} /[^123]/ {
if ($0 == "quit") {
print "goodbye";
exit;
}
else {
invalid();
prompt();
}
}
function prompt(){
print "enter your choice (or type quit to exit): ";
}
function invalid(){
print "invalid move";
}
function newgame() {
print "\n---- NEW GAME ----\n";
print "\nThe running total is currently zero.\n";
total = 0;
if (rand() < 0.5) {
print "The first move is AI move.\n";
update("ai", best[total % 4]);
}
else
print "The first move is human move.\n";
}
function update(player, move) {
printf "%8s: %d = %d + %d\n\n", player, total + move, total, move;
total += move;
if (total == GOAL) {
printf "The winner is %s.\n\n", player;
newgame();
}
}</lang>
- Output:
gawk -f Game21.awk
21 Game
21 is a two player game, the game is played by choosing a number
(1, 2, or 3) to be added to the running total. The game is won by
the player whose chosen number causes the running total to reach
exactly 21. The running total starts at zero.
---- NEW GAME ----
The running total is currently zero.
The first move is human move.
enter your choice (or type quit to exit):
1
human: 1 = 0 + 1
ai: 2 = 1 + 1
enter your choice (or type quit to exit):
2
human: 4 = 2 + 2
ai: 5 = 4 + 1
enter your choice (or type quit to exit):
3
human: 8 = 5 + 3
ai: 9 = 8 + 1
enter your choice (or type quit to exit):
1
human: 10 = 9 + 1
ai: 13 = 10 + 3
enter your choice (or type quit to exit):
2
human: 15 = 13 + 2
ai: 17 = 15 + 2
enter your choice (or type quit to exit):
1
human: 18 = 17 + 1
ai: 21 = 18 + 3
The winner is ai.
---- NEW GAME ----
The running total is currently zero.
The first move is human move.
enter your choice (or type quit to exit):
wow
invalid move
222
invalid move
enter your choice (or type quit to exit):
1
human: 1 = 0 + 1
ai: 2 = 1 + 1
enter your choice (or type quit to exit):
quit
goodbye
bash
<lang bash>shopt -s expand_aliases alias bind_variables=' {
local -ri goal_count=21 local -ri player_human=0 local -ri player_computer=1 local -i turn=1 local -i total_count=0 local -i input_number=0 local -i choose_turn=0
} ' whose_turn() {
case $(( ( turn + choose_turn ) % 2 )) in
${player_human}) echo "player";;
${player_computer}) echo "computer";;
esac
} next_turn() {
let turn++
} validate_number() {
! test ${input_number} -ge 1 -a ${input_number} -le $( max_guess )
} prompt_number() {
local prompt_str
test $( max_guess ) -eq 1 && {
prompt_str="enter the number 1 to win"
true
} || {
prompt_str="enter a number between 1 and $( max_guess )"
}
while [ ! ]
do
read -p "${prompt_str} (or quit): "
input_number=${REPLY}
case ${REPLY} in
"quit") {
false
return
} ;;
esac
validate_number || break
echo "try again"
done
} update_count() {
let total_count+=input_number
} remaining_count() {
echo $(( goal_count - total_count ))
} max_guess() {
local -i remaining_count
remaining_count=$( remaining_count )
case $( remaining_count ) in
1|2|3) echo ${remaining_count} ;;
*) echo 3 ;;
esac
} iter() {
update_count next_turn
} on_game_over() {
test ! ${input_number} -eq $( remaining_count ) || {
test ! "$( whose_turn )" = "player" && {
echo -ne "\nYou won!\n\n"
true
} || {
echo -ne "\nThe computer won!\nGAME OVER\n\n"
}
false
}
} on_game_start() {
echo 21 Game read -p "Press enter key to start"
} choose_turn() {
let choose_turn=${RANDOM}%2
} choose_number() {
local -i remaining_count
remaining_count=$( remaining_count )
case ${remaining_count} in
1|2|3) {
input_number=${remaining_count}
} ;;
5|6|7) {
let input_number=remaining_count-4
} ;;
*) {
let input_number=${RANDOM}%$(( $( max_guess ) - 1 ))+1
}
esac
} game_play() {
choose_turn
while [ ! ]
do
echo "Total now ${total_count} (remaining: $( remaining_count ))"
echo -ne "Turn: ${turn} ("
test ! "$( whose_turn )" = "player" && {
echo -n "Your"
true
} || {
echo -n "Computer"
}
echo " turn)"
test ! "$( whose_turn )" = "player" && {
prompt_number || break
true
} || {
choose_number
sleep 2
echo "Computer chose ${input_number}"
}
on_game_over || break
sleep 1
iter
done
} 21_Game() {
bind_variables on_game_start game_play
} if [ ${#} -eq 0 ] then
true
else
exit 1
fi 21_Game </lang>
C
<lang C>/**
* Game 21 - an example in C language for Rosseta Code. * * A simple game program whose rules are described below * - see DESCRIPTION string. * * This program should be compatible with C89 and up. */
/*
* Turn off MS Visual Studio panic warnings which disable to use old gold * library functions like printf, scanf etc. This definition should be harmless * for non-MS compilers. */
- define _CRT_SECURE_NO_WARNINGS
- include <stdio.h>
- include <stdlib.h>
- include <time.h>
/*
* Define bool, true and false as needed. The stdbool.h is a standard header * in C99, therefore for older compilers we need DIY booleans. BTW, there is * no __STDC__VERSION__ predefined macro in MS Visual C, therefore we need * check also _MSC_VER. */
- if __STDC_VERSION__ >= 199901L || _MSC_VER >= 1800
- include <stdbool.h>
- else
- define bool int
- define true 1
- define false 0
- endif
- define GOAL 21
- define NUMBER_OF_PLAYERS 2
- define MIN_MOVE 1
- define MAX_MOVE 3
- define BUFFER_SIZE 256
- define _(STRING) STRING
/*
* Spaces are meaningful: on some systems they can be visible. */
static char DESCRIPTION[] =
"21 Game \n" " \n" "21 is a two player game, the game is played by choosing a number \n" "(1, 2, or 3) to be added to the running total. The game is won by\n" "the player whose chosen number causes the running total to reach \n" "exactly 21. The running total starts at zero. \n\n";
static int total;
void update(char* player, int move)
{
printf("%8s: %d = %d + %d\n\n", player, total + move, total, move);
total += move;
if (total == GOAL)
printf(_("The winner is %s.\n\n"), player);
}
int ai()
{
/*
* There is a winning strategy for the first player. The second player can win * then and only then the frist player does not use the winning strategy. * * The winning strategy may be defined as best move for the given running total. * The running total is a number from 0 to GOAL. Therefore, for given GOAL, best * moves may be precomputed (and stored in a lookup table). Actually (when legal * moves are 1 or 2 or 3) the table may be truncated to four first elements. */
- if GOAL < 32 && MIN_MOVE == 1 && MAX_MOVE == 3
static const int precomputed[] = { 1, 1, 3, 2, 1, 1, 3, 2, 1, 1, 3, 2, 1, 1,
3, 2, 1, 1, 3, 2, 1, 1, 3, 2, 1, 1, 3, 2, 1, 1, 3 };
update(_("ai"), precomputed[total]);
- elif MIN_MOVE == 1 && MAX_MOVE == 3
static const int precomputed[] = { 1, 1, 3, 2};
update(_("ai"), precomputed[total % (MAX_MOVE + 1)]);
- else
int i;
int move = 1;
for (i = MIN_MOVE; i <= MAX_MOVE; i++)
if ((total + i - 1) % (MAX_MOVE + 1) == 0)
move = i;
for (i = MIN_MOVE; i <= MAX_MOVE; i++)
if (total + i == GOAL)
move = i;
update(_("ai"), move);
- endif
}
void human(void)
{
char buffer[BUFFER_SIZE];
int move;
while ( printf(_("enter your move to play (or enter 0 to exit game): ")),
fgets(buffer, BUFFER_SIZE, stdin),
sscanf(buffer, "%d", &move) != 1 ||
(move && (move < MIN_MOVE || move > MAX_MOVE || total+move > GOAL)))
puts(_("\nYour answer is not a valid choice.\n"));
putchar('\n');
if (!move) exit(EXIT_SUCCESS);
update(_("human"), move);
}
int main(int argc, char* argv[])
{
srand(time(NULL));
puts(_(DESCRIPTION));
while (true)
{
puts(_("\n---- NEW GAME ----\n"));
puts(_("\nThe running total is currently zero.\n"));
total = 0;
if (rand() % NUMBER_OF_PLAYERS)
{
puts(_("The first move is AI move.\n"));
ai();
}
else
puts(_("The first move is human move.\n"));
while (total < GOAL)
{
human();
ai();
}
}
}</lang>
- Output:
21 Game
21 is a two player game, the game is played by choosing a number
(1, 2, or 3) to be added to the running total. The game is won by
the player whose chosen number causes the running total to reach
exactly 21. The running total starts at zero.
---- NEW GAME ----
The running total is currently zero.
The first move is AI move.
AI: 1 = 0 + 1
enter your move to play (or enter 0 to exit game): 1
human: 2 = 1 + 1
AI: 5 = 2 + 3
enter your move to play (or enter 0 to exit game): 3
human: 6 = 5 + 1
AI: 9 = 6 + 3
enter your move to play (or enter 0 to exit game): asd ?
Your answer is not a valid choice.
enter your move to play (or enter 0 to exit game): -1
Your answer is not a valid choice.
enter your move to play (or enter 0 to exit game): 4
Your answer is not a valid choice.
enter your move to play (or enter 0 to exit game): 2
human: 10 = 9 + 1
AI: 13 = 10 + 3
enter your move to play (or enter 0 to exit game): 3
human: 14 = 13 + 1
AI: 17 = 14 + 3
enter your move to play (or enter 0 to exit game): 2
human: 18 = 17 + 1
AI: 21 = 18 + 3
The winner is AI.
---- NEW GAME ----
The running total is currently zero.
The first move is AI move.
AI: 1 = 0 + 1
enter your move to play (or enter 0 to exit game): 1
human: 2 = 1 + 1
AI: 5 = 2 + 3
enter your move to play (or enter 0 to exit game): 2
human: 6 = 5 + 1
AI: 9 = 6 + 3
enter your move to play (or enter 0 to exit game): 3
human: 10 = 9 + 1
AI: 13 = 10 + 3
enter your move to play (or enter 0 to exit game): 0
C++
Model View Controller
<lang cpp>/**
* Game 21 - an example in C++ language for Rosseta Code. * * This version is an example of MVC architecture. It seems be a little cleaner * than MVP. The friendship has broken encapsulations to avoid getters. */
- include <cstdlib>
- include <ctime>
- include <iostream>
- include <iomanip>
- include <limits>
using namespace std;
- define _(STR) STR
class Model
{
public:
static const int GOAL = 21; static const int NUMBER_OF_PLAYERS = 2; static const int MIN_MOVE = 1; static const int MAX_MOVE = 3; int bestMove(); bool update(const char* player, int move); bool isGameBegin(); bool isGameOver();
protected:
friend class View; View* view = nullptr; const char* player = nullptr; int oldTotal = 0; int newTotal = 0; int lastMove = 0;
};
class View
{
protected:
Model* model;
public:
View(Model* model); void init(const char* player); void update();
};
class Controller
{
protected:
Model* model; View* view;
public:
Controller(Model* model, View* view); int input(); void clear(); void run();
};
int Model::bestMove()
{
// This is not the fastest algorithm. There is possible to precompute // and memorize all answers before game begin or even hard code them.
int move = MIN_MOVE;
for (int i = MIN_MOVE; i <= MAX_MOVE; i++)
if ((newTotal + i - 1) % (MAX_MOVE + 1) == 0)
move = i;
for (int i = MIN_MOVE; i <= MAX_MOVE; i++)
if (newTotal + i == GOAL)
move = i;
return move;
}
bool Model::update(const char* player, int move) {
if (move >= MIN_MOVE && move <= MAX_MOVE && newTotal + move <= GOAL)
{
this->player = player;
oldTotal = newTotal;
newTotal = oldTotal + move;
lastMove = move;
view->update();
return true;
}
else
return false;
}
bool Model::isGameBegin() {
return oldTotal == 0;
}
bool Model::isGameOver() {
return newTotal == GOAL;
}
View::View(Model* model)
{
this->model = model; model->view = this;
}
void View::init(const char* player) {
if (model->newTotal == 0)
cout << _("----NEW GAME----\n\n")
<< _("The running total is currently zero.\n")
<< _("The first move is ") << player << _(" move.\n\n");
}
void View::update() {
cout << setw(8) << model->player << ": " << model->newTotal << " = "
<< model->oldTotal << " + " << model->lastMove << endl << endl;
if (model->isGameOver())
cout << endl << _("The winner is ") << model->player << _(".\n\n\n");
}
Controller::Controller(Model* model, View* view)
{
this->model = model; this->view = view;
}
void Controller::run() {
if (rand() % Model::NUMBER_OF_PLAYERS == 0)
{
view->init("AI");
model->update("AI", model->bestMove());
}
else
view->init("human");
while (!model->isGameOver())
{
while (!model->update("human", input()))
clear();
model->update("AI", model->bestMove());
}
}
int Controller::input() {
int value;
cout << _("enter a valid number to play (or enter 0 to exit game): ");
cin >> value;
cout << endl;
if (!cin.fail())
{
if (value == 0)
exit(EXIT_SUCCESS);
else
return value;
}
else
return model->MIN_MOVE - 1;
}
void Controller::clear() {
cout << _("Your answer is not a valid choice.") << endl;
cin.clear();
cin.ignore((streamsize)numeric_limits<int>::max, '\n');
}
int main(int argc, char* argv)
{
srand(time(NULL));
cout << _(
"21 Game \n"
" \n"
"21 is a two player game, the game is played by choosing a number \n"
"(1, 2, or 3) to be added to the running total. The game is won by\n"
"the player whose chosen number causes the running total to reach \n"
"exactly 21. The running total starts at zero. \n\n");
while (true)
{
Model* model = new Model();
View* view = new View(model);
Controller* controler = new Controller(model, view);
controler->run();
delete controler;
delete model;
delete view;
}
return EXIT_SUCCESS; // dead code
}</lang>
Model View Presenter
<lang cpp>/**
* Game 21 - an example in C++ language for Rosseta Code. * * This version is an example of MVP architecture. The user input, as well as * the AI opponent, is handled by separate passive subclasses of abstract class * named Controller. It can be noticed that the architecture support OCP, * for an example the AI module can be "easily" replaced by another AI etc. * * BTW, it would be better to place each class in its own file. But it would * be less convinient for Rosseta Code, where "one solution" mean "one file". */
- include <cstdlib>
- include <ctime>
- include <iostream>
- include <iomanip>
- include <limits>
using namespace std;
- define _(STR) STR
class Model
{
protected:
int oldTotal; int newTotal; int lastMove;
public:
static const int GOAL = 21; static const int NUMBER_OF_PLAYERS = 2;
Model()
{
newTotal = 0;
oldTotal = 0;
lastMove = 0;
}
void update(int move)
{
oldTotal = newTotal;
newTotal = oldTotal + move;
lastMove = move;
}
int getOldTotal()
{
return oldTotal;
}
int getNewTotal()
{
return newTotal;
}
int getLastMove()
{
return lastMove;
}
bool isEndGame()
{
return newTotal == GOAL;
}
};
class View
{
public:
void update(string comment, Model* model)
{
cout << setw(8) << comment << ": "
<< model->getNewTotal()
<< " = "
<< model->getOldTotal()
<< " + "
<< model->getLastMove() << endl
<< endl;
}
void newGame(string player)
{
cout << _("----NEW GAME----") << endl
<< endl
<< _("The running total is currently zero.") << endl
<< endl
<< _("The first move is ") << player << _(" move.") << endl
<< endl;
}
void endGame(string name)
{
cout << endl << _("The winner is ") << name << _(".") << endl
<< endl
<< endl;
}
};
class Controller
{
public:
virtual string getName() = 0; virtual int getMove(Model* model) = 0;
};
class AI : public Controller
{
public:
string getName()
{
return _("AI");
}
int getMove(Model* model)
{
int n = model->getNewTotal();
for (int i = 1; i <= 3; i++)
if (n + i == Model::GOAL)
return i;
for (int i = 1; i <= 3; i++)
if ((n + i - 1) % 4 == 0)
return i;
return 1 + rand() % 3;
}
};
class Human : public Controller
{
public:
string getName()
{
return _("human");
}
int getMove(Model* model)
{
int n = model->getNewTotal();
int value;
while (true) {
if (n == Model::GOAL - 1)
cout << _("enter 1 to play (or enter 0 to exit game): ");
else if (n == Model::GOAL - 2)
cout << _("enter 1 or 2 to play (or enter 0 to exit game): ");
else
cout << _("enter 1 or 2 or 3 to play (or enter 0 to exit game): ");
cin >> value;
if (!cin.fail()) {
if (value == 0)
exit(0);
else if (value >= 1 && value <= 3 && n + value <= Model::GOAL)
{
cout << endl;
return value;
}
}
cout << _("Your answer is not a valid choice.") << endl;
cin.clear();
cin.ignore((streamsize)numeric_limits<int>::max, '\n');
}
}
};
class Presenter
{
protected:
Model* model; View* view; Controller** controllers;
public:
Presenter(Model* model, View* view, Controller** controllers)
{
this->model = model;
this->view = view;
this->controllers = controllers;
}
void run()
{
int player = rand() % Model::NUMBER_OF_PLAYERS;
view->newGame(controllers[player]->getName());
while (true)
{
Controller* controller = controllers[player];
model->update(controller->getMove(model));
view->update(controller->getName(), model);
if (model->isEndGame())
{
view->endGame(controllers[player]->getName());
break;
}
player = (player + 1) % Model::NUMBER_OF_PLAYERS;
}
}
};
int main(int argc, char* argv)
{
srand(time(NULL));
while (true)
{
Model* model = new Model();
View* view = new View();
Controller* controllers[Model::NUMBER_OF_PLAYERS];
controllers[0] = new Human();
for (int i = 1; i < Model::NUMBER_OF_PLAYERS; i++)
controllers[i] = new AI();
Presenter* presenter = new Presenter(model, view, controllers);
presenter->run();
delete model;
delete view;
delete controllers[0];
delete controllers[1];
delete presenter;
}
return EXIT_SUCCESS; // dead code
} </lang>
- Output:
----NEW GAME----
The running total is currently zero.
The first move is human move.
enter 1 or 2 or 3 to play (or enter 0 to exit game): 1
human: 1 = 0 + 1
AI: 4 = 1 + 3
enter 1 or 2 or 3 to play (or enter 0 to exit game): 2
human: 6 = 4 + 2
AI: 9 = 6 + 3
enter 1 or 2 or 3 to play (or enter 0 to exit game): nope
Your answer is not a valid choice.
enter 1 or 2 or 3 to play (or enter 0 to exit game): 8
Your answer is not a valid choice.
enter 1 or 2 or 3 to play (or enter 0 to exit game): 3
human: 12 = 9 + 3
AI: 13 = 12 + 1
enter 1 or 2 or 3 to play (or enter 0 to exit game): 2
human: 15 = 13 + 2
AI: 17 = 15 + 2
enter 1 or 2 or 3 to play (or enter 0 to exit game): 3
human: 20 = 17 + 3
AI: 21 = 20 + 1
The winner is AI.
----NEW GAME----
The running total is currently zero.
The first move is human move.
enter 1 or 2 or 3 to play (or enter 0 to exit game): 1
human: 1 = 0 + 1
AI: 4 = 1 + 3
enter 1 or 2 or 3 to play (or enter 0 to exit game): 2
human: 6 = 4 + 2
AI: 9 = 6 + 3
enter 1 or 2 or 3 to play (or enter 0 to exit game): 3
human: 12 = 9 + 3
AI: 13 = 12 + 1
enter 1 or 2 or 3 to play (or enter 0 to exit game): 0
C#
<lang csharp>// 21 Game
using System;
namespace _21Game {
public class Program
{
private const string computerPlayer = "Computer";
private const string humanPlayer = "Player 1";
public static string SwapPlayer(string currentPlayer)
{
if (currentPlayer == computerPlayer)
{
currentPlayer = humanPlayer;
}
else
{
currentPlayer = computerPlayer;
}
return currentPlayer;
}
public static void PlayGame()
{
bool playAnother = true;
int total = 0;
int final = 21;
int roundChoice = 0;
string currentPlayer = RandomPLayerSelect();
int compWins = 0;
int humanWins = 0;
while (playAnother)
{
Console.WriteLine($"Now playing: {currentPlayer}");
try
{
if (currentPlayer == computerPlayer)
{
roundChoice = CompMove(total);
}
else
{
roundChoice = int.Parse(Console.ReadLine());
}
if (roundChoice != 1 && roundChoice != 2 && roundChoice != 3)
{
throw new Exception();
}
total += roundChoice;
}
catch (Exception)
{
Console.WriteLine("Invalid choice! Choose from numbers: 1, 2, 3.");
continue;
}
Console.WriteLine(total);
if (total == final)
{
if (currentPlayer == computerPlayer)
{
compWins++;
}
if (currentPlayer == humanPlayer)
{
humanWins++;
}
Console.WriteLine($"Winner: {currentPlayer}");
Console.WriteLine($"Comp wins: {compWins}. Human wins: {humanWins}");
Console.WriteLine($"do you wan to play another round? y/n");
var choice = Console.ReadLine();
if (choice == "y")
{
total = 0;
}
else if (choice == "n")
{
break;
}
else
{
Console.WriteLine("Invalid choice! Choose from y or n");
continue;
}
}
else if (total > 21)
{
Console.WriteLine("Not the right time to play this game :)");
break;
}
currentPlayer = SwapPlayer(currentPlayer);
}
}
public static bool CheckIfCanWin(int total)
{
bool result = false;
if (total == 18)
{
result = true;
}
return result;
}
public static int CompMove(int total)
{
int choice = 0;
if (CheckIfCanWin(total))
{
choice = 21 - total;
}
else
{
choice = new Random().Next(1,4);
}
return choice;
}
public static string RandomPLayerSelect()
{
string[] players = new string[] { computerPlayer, humanPlayer };
var random = new Random().Next(0,2);
return players[random];
}
public static void Main(string[] args)
{
// welcome message and rules
Console.WriteLine("Welcome to 21 game \n");
Console.WriteLine(@"21 is a two player game.
The game is played by choosing a number. 1, 2, or 3 to be added a total sum. \n The game is won by the player reaches exactly 21. \n" );
Console.WriteLine("Choose your number: (1, 2 or 3)");
PlayGame();
}
}
}
</lang>
Delphi
See Pascal[1]
Factor
A difficulty system has been implemented. The player chooses a difficulty from 1-10. There is a difficulty in 10 chance that the computer opponent gets to move first. There is a difficulty in 10 chance each turn that the computer opponent will make the optimal move (i.e. setting the total to a number of the form 4n+1) as opposed to a random move. At difficulty level 10, it is impossible for the human player to win the game.
<lang factor>USING: accessors combinators.random continuations formatting io kernel math math.functions math.parser multiline qw random sequences ; IN: rosetta-code.21-game
STRING: welcome 21 is a two-player game. The game is played by choosing a number (1, 2, or 3) to be added to the running total.
The game is won by the player whose chosen number causes the running total to reach 21.
One player will be the computer. Players alternate supplying a number to be added to the running total.
- .welcome ( -- ) welcome print ;
SYMBOLS: +computer+ +human+ ;
TUPLE: game total difficulty who ;
! Instead of saying something dry like 'invalid input,' spice ! it up a little.
- insult ( -- )
{
"No." "Er..." "Learn to read." "I think not."
"Come on, is it really this difficult?"
} random print ;
- get-input ( options-seq prompt-str -- str )
dup "%s: " printf flush readln dup reach member? [ 2nip ] [ drop insult get-input ] if ;
- get-integer ( options-seq prompt-str -- n )
get-input string>number ;
- get-difficulty ( -- x )
qw{ 1 2 3 4 5 6 7 8 9 10 }
"Difficulty (1-10)" get-integer 10 / ;
- human-move ( game -- n )
drop qw{ q 1 2 3 } "Your move (1-3) or q to quit" get-input
dup "q" = [ drop return ] when string>number ;
- choose-first-player ( difficulty -- player )
[ +computer+ ] [ +human+ ] ifp ;
- <game> ( -- game )
0 get-difficulty dup choose-first-player game boa ;
- swap-player ( game -- )
[ +human+ = +computer+ +human+ ? ] change-who drop ;
- .total ( game -- ) total>> "Running total: %d\n" printf ;
- random-move ( game -- n ) drop 3 random 1 + ;
- boundary? ( n -- ? ) 1 - 4 divisor? ;
- (optimal-move) ( m -- n ) dup 4 / ceiling 4 * 1 + swap - ;
- optimal-move ( game -- n )
total>> dup boundary? [ random-move ] [ (optimal-move) ] if ;
- computer-move ( game -- n )
dup difficulty>> [ optimal-move ] [ random-move ] ifp dup "Computer chose %d.\n" printf ;
- do-turn ( game -- )
dup dup who>> +human+ = [ human-move ] [ computer-move ] if [ + ] curry change-total dup .total swap-player ;
- do-turns ( game -- )
[ dup total>> 20 > ] [ dup do-turn ] until dup swap-player who>> "%u wins!\n" printf ;
- play-21-game ( -- )
.welcome nl [ <game> do-turns ] with-return ;
MAIN: play-21-game</lang>
- Output:
21 is a two-player game. The game is played by choosing a number (1, 2, or 3) to be added to the running total. The game is won by the player whose chosen number causes the running total to reach 21. One player will be the computer. Players alternate supplying a number to be added to the running total. Difficulty (1-10): 3 Your move (1-3) or q to quit: 3 Running total: 3 Computer chose 2. Running total: 5 Your move (1-3) or q to quit: 2 Running total: 7 Computer chose 2. Running total: 9 Your move (1-3) or q to quit: 1 Running total: 10 Computer chose 3. Running total: 13 Your move (1-3) or q to quit: apple Er... Your move (1-3) or q to quit: 3 Running total: 16 Computer chose 1. Running total: 17 Your move (1-3) or q to quit: 1 Running total: 18 Computer chose 1. Running total: 19 Your move (1-3) or q to quit: 2 Running total: 21 +human+ wins!
Fortran
<lang Fortran>! game 21 - an example in modern fortran language for rosseta code.
subroutine ai
common itotal, igoal
if (itotal .lt. igoal) then
move = 1
do i = 1, 3
if (mod(itotal + i - 1 , 4) .eq. 0) then
move = i
end if
end do
do i = 1, 3
if (itotal + i .eq. igoal) then
move = i
end if
end do
print *, " ai ", itotal + move, " = ", itotal, " + ", move
itotal = itotal + move
if (itotal .eq. igoal) then
print *, ""
print *, "the winner is ai"
print *, ""
end if
end if
end subroutine ai
subroutine human
common itotal, igoal
print *, ""
do while (.true.)
if (itotal + 1 .eq. igoal) then
print *, "enter 1 (or 0 to exit): "
else if (itotal + 2 .eq. igoal) then
print *, "enter 1 or 2 (or 0 to exit): "
else
print *, "enter 1 or 2 or 3 (or 0 to exit)"
end if
read(*,*) move
if (move .eq. 0) then
stop
else if (move .ge. 1 .and. move .le. 3 .and. move + itotal .le. igoal) then
print *, " human ", itotal + move, " = ", itotal, " + ", move
itotal = itotal + move
if (itotal .eq. igoal) then
print *, ""
print *, "the winner is human"
print *, ""
end if
return
else
print *, "a bad choice"
end if
end do
end subroutine human
program main
common itotal, igoal
print *,"game 21 - an example in fortran iv language for rosseta code."
print *,""
print *,"21 is a two player game, the game is played by choosing a number"
print *,"(1, 2, or 3) to be added to the running total. the game is won"
print *,"by the player whose chosen number causes the running total to reach"
print *,"exactly 21. the running total starts at zero."
print *,""
i = irand(1)
igoal = 21
do while(.true.)
print *, "---- new game ----"
print *, ""
print *, "the running total is currently zero."
print *, ""
itotal = 0
if (mod(irand(0), 2) .eq. 0) then
print *, "the first move is ai move."
call ai
else
print *, "the first move is human move."
end if
print *, ""
do while(itotal .lt. igoal)
call human
call ai
end do
end do end program main</lang>
- Output:
game 21 - an example in fortran language for rosseta code.
21 is a two player game, the game is played by choosing a number
(1, 2, or 3) to be added to the running total. the game is won
by the player whose chosen number causes the running total to reach
exactly 21. the running total starts at zero.
---- new game ----
the running total is currently zero.
the first move is human move.
enter 1 or 2 or 3 (or 0 to exit)
1
human 1 = 0 + 1
ai 2 = 1 + 1
enter 1 or 2 or 3 (or 0 to exit)
3
human 5 = 2 + 3
ai 6 = 5 + 1
enter 1 or 2 or 3 (or 0 to exit)
4
a bad choice
enter 1 or 2 or 3 (or 0 to exit)
3
human 9 = 6 + 3
ai 10 = 9 + 1
enter 1 or 2 or 3 (or 0 to exit)
2
human 12 = 10 + 2
ai 13 = 12 + 1
enter 1 or 2 or 3 (or 0 to exit)
3
human 16 = 13 + 3
ai 17 = 16 + 1
enter 1 or 2 or 3 (or 0 to exit)
2
human 19 = 17 + 2
ai 21 = 19 + 2
the winner is ai
---- new game ----
the running total is currently zero.
the first move is human move.
enter 1 or 2 or 3 (or 0 to exit)
0
Go
To give the human player a reasonable chance whoever goes first, the computer always chooses randomly when the running total is below 18 but otherwise chooses the exact number needed to win the game. <lang go>package main
import (
"bufio" "fmt" "log" "math/rand" "os" "strconv" "time"
)
var scanner = bufio.NewScanner(os.Stdin)
var (
total = 0 quit = false
)
func itob(i int) bool {
if i == 0 {
return false
}
return true
}
func getChoice() {
for {
fmt.Print("Your choice 1 to 3 : ")
scanner.Scan()
if scerr := scanner.Err(); scerr != nil {
log.Fatalln(scerr, "when choosing number")
}
text := scanner.Text()
if text == "q" || text == "Q" {
quit = true
return
}
input, err := strconv.Atoi(text)
if err != nil {
fmt.Println("Invalid number, try again")
continue
}
newTotal := total + input
switch {
case input < 1 || input > 3:
fmt.Println("Out of range, try again")
case newTotal > 21:
fmt.Println("Too big, try again")
default:
total = newTotal
fmt.Println("Running total is now", total)
return
}
}
}
func main() {
rand.Seed(time.Now().UnixNano())
computer := itob(rand.Intn(2))
fmt.Println("Enter q to quit at any time\n")
if computer {
fmt.Println("The computer will choose first")
} else {
fmt.Println("You will choose first")
}
fmt.Println("\nRunning total is now 0\n")
var choice int
for round := 1; ; round++ {
fmt.Printf("ROUND %d:\n\n", round)
for i := 0; i < 2; i++ {
if computer {
if total < 18 {
choice = 1 + rand.Intn(3)
} else {
choice = 21 - total
}
total += choice
fmt.Println("The computer chooses", choice)
fmt.Println("Running total is now", total)
if total == 21 {
fmt.Println("\nSo, commiserations, the computer has won!")
return
}
} else {
getChoice()
if quit {
fmt.Println("OK, quitting the game")
return
}
if total == 21 {
fmt.Println("\nSo, congratulations, you've won!")
return
}
}
fmt.Println()
computer = !computer
}
}
}</lang>
- Output:
A sample game where the human player manages to win even though the computer (chosen randomly) goes first.
Enter q to quit at any time The computer will choose first Running total is now 0 ROUND 1: The computer chooses 1 Running total is now 1 Your choice 1 to 3 : 3 Running total is now 4 ROUND 2: The computer chooses 2 Running total is now 6 Your choice 1 to 3 : 4 Out of range, try again Your choice 1 to 3 : 3 Running total is now 9 ROUND 3: The computer chooses 2 Running total is now 11 Your choice 1 to 3 : 2 Running total is now 13 ROUND 4: The computer chooses 2 Running total is now 15 Your choice 1 to 3 : 2 Running total is now 17 ROUND 5: The computer chooses 1 Running total is now 18 Your choice 1 to 3 : 3 Running total is now 21 So, congratulations, you've won!
A sample game where the human player plays sensibly but still loses when the computer goes first.
Enter q to quit at any time The computer will choose first Running total is now 0 ROUND 1: The computer chooses 3 Running total is now 3 Your choice 1 to 3 : 3 Running total is now 6 ROUND 2: The computer chooses 3 Running total is now 9 Your choice 1 to 3 : 3 Running total is now 12 ROUND 3: The computer chooses 1 Running total is now 13 Your choice 1 to 3 : 3 Running total is now 16 ROUND 4: The computer chooses 1 Running total is now 17 Your choice 1 to 3 : 1 Running total is now 18 ROUND 5: The computer chooses 3 Running total is now 21 So, commiserations, the computer has won!
Haskell
The computer chooses values randomly. <lang haskell>import System.Random import System.IO import System.Exit import Control.Monad import Text.Read import Data.Maybe
promptAgain :: IO Int promptAgain = do
putStrLn "Invalid input - must be a number among 1,2 or 3. Try again." playerMove
playerMove :: IO Int playerMove = do
putStr "Your choice(1 to 3):"
number <- getLine
when (number == "q") $ do
exitWith ExitSuccess
let n = readMaybe number :: Maybe Int
x <- if isNothing n
then promptAgain
else let val = read number
in if (val > 3 || val < 1)
then promptAgain
else return val
return x
computerMove :: IO Int computerMove = do
x <- randomRIO (1, 3) putStrLn $ "Computer move:" ++ (show x) return x
gameLoop :: (IO Int, IO Int) -> IO Int gameLoop moveorder = loop moveorder 0
where loop moveorder total = do
number <- fst moveorder
let total1 = number + total
putStrLn $ "Running total:" ++ (show total1)
if total1 >= 21
then return 0
else do
number <- snd moveorder
let total2 = number + total1
putStrLn $ "Running total:" ++ (show total2)
if total2 >= 21
then return 1
else loop moveorder total2
main :: IO () main = do
hSetBuffering stdout $ BlockBuffering $ Just 1
putStrLn "Enter q to quit at any time"
x <- randomRIO (0, 1) :: IO Int
let (moveorder, names) = if x == 0
then ((playerMove, computerMove), ("Player", "Computer"))
else ((computerMove, playerMove), ("Computer", "Player"))
when (x == 1) $ do
putStrLn "Computer will start the game"
y <- gameLoop moveorder
when (y == 0) $ do
putStrLn $ (fst names) ++ " has won the game"
when (y == 1) $ do
putStrLn $ (snd names) ++ " has won the game"</lang>
Java
Options for creating a game:
- Who goes first on the first game. Thereafter, the winner of the current game goes first on the next game.
- The value needed to win the game.
- Valid values allowed to select on each turn.
Sample output provided for options as follows:
- Computer goes first on the first game.
- Value needed to win game is 21.
- Valid values to select is 1, 2, or 3.
The computer strategy is to see if a valid value will win the game. If so, that value is selected. Otherwise, a random value among the valid values is selected.
<lang java> import java.util.Random; import java.util.Scanner;
public class TwentyOneGame {
public static void main(String[] args) {
new TwentyOneGame().run(true, 21, new int[] {1, 2, 3});
}
public void run(boolean computerPlay, int max, int[] valid) {
String comma = "";
for ( int i = 0 ; i < valid.length ; i++ ) {
comma += valid[i];
if ( i < valid.length - 2 && valid.length >= 3 ) {
comma += ", ";
}
if ( i == valid.length - 2 ) {
comma += " or ";
}
}
System.out.printf("The %d game.%nEach player chooses to add %s to a running total.%n" +
"The player whose turn it is when the total reaches %d will win the game.%n" +
"Winner of the game starts the next game. Enter q to quit.%n%n", max, comma, max);
int cGames = 0;
int hGames = 0;
boolean anotherGame = true;
try (Scanner scanner = new Scanner(System.in);) {
while ( anotherGame ) {
Random r = new Random();
int round = 0;
int total = 0;
System.out.printf("Start game %d%n", hGames + cGames + 1);
DONE:
while ( true ) {
round++;
System.out.printf("ROUND %d:%n%n", round);
for ( int play = 0 ; play < 2 ; play++ ) {
if ( computerPlay ) {
int guess = 0;
// try find one equal
for ( int test : valid ) {
if ( total + test == max ) {
guess = test;
break;
}
}
// try find one greater than
if ( guess == 0 ) {
for ( int test : valid ) {
if ( total + test >= max ) {
guess = test;
break;
}
}
}
if ( guess == 0 ) {
guess = valid[r.nextInt(valid.length)];
}
total += guess;
System.out.printf("The computer chooses %d%n", guess);
System.out.printf("Running total is now %d%n%n", total);
if ( total >= max ) {
break DONE;
}
}
else {
while ( true ) {
System.out.printf("Your choice among %s: ", comma);
String line = scanner.nextLine();
if ( line.matches("^[qQ].*") ) {
System.out.printf("Computer wins %d game%s, human wins %d game%s. One game incomplete.%nQuitting.%n", cGames, cGames == 1 ? "" : "s", hGames, hGames == 1 ? "" : "s");
return;
}
try {
int input = Integer.parseInt(line);
boolean inputOk = false;
for ( int test : valid ) {
if ( input == test ) {
inputOk = true;
break;
}
}
if ( inputOk ) {
total += input;
System.out.printf("Running total is now %d%n%n", total);
if ( total >= max ) {
break DONE;
}
break;
}
else {
System.out.printf("Invalid input - must be a number among %s. Try again.%n", comma);
}
}
catch (NumberFormatException e) {
System.out.printf("Invalid input - must be a number among %s. Try again.%n", comma);
}
}
}
computerPlay = !computerPlay;
}
}
String win;
if ( computerPlay ) {
win = "Computer wins!!";
cGames++;
}
else {
win = "You win and probably had help from another computer!!";
hGames++;
}
System.out.printf("%s%n", win);
System.out.printf("Computer wins %d game%s, human wins %d game%s%n%n", cGames, cGames == 1 ? "" : "s", hGames, hGames == 1 ? "" : "s");
while ( true ) {
System.out.printf("Another game (y/n)? ");
String line = scanner.nextLine();
if ( line.matches("^[yY]$") ) {
// OK
System.out.printf("%n");
break;
}
else if ( line.matches("^[nN]$") ) {
anotherGame = false;
System.out.printf("Quitting.%n");
break;
}
else {
System.out.printf("Invalid input - must be a y or n. Try again.%n");
}
}
}
}
}
} </lang>
- Output:
A sample of 3 games.
The 21 game. Each player chooses to add 1, 2 or 3 to a running total. The player whose turn it is when the total reaches 21 will win the game. Winner of the game starts the next game. Enter q to quit. Start game 1 ROUND 1: The computer chooses 3 Running total is now 3 Your choice among 1, 2 or 3: 4 Invalid input - must be a number among 1, 2 or 3. Try again. Your choice among 1, 2 or 3: r Invalid input - must be a number among 1, 2 or 3. Try again. Your choice among 1, 2 or 3: 1 Running total is now 4 ROUND 2: The computer chooses 1 Running total is now 5 Your choice among 1, 2 or 3: 3 Running total is now 8 ROUND 3: The computer chooses 1 Running total is now 9 Your choice among 1, 2 or 3: 3 Running total is now 12 ROUND 4: The computer chooses 3 Running total is now 15 Your choice among 1, 2 or 3: 2 Running total is now 17 ROUND 5: The computer chooses 3 Running total is now 20 Your choice among 1, 2 or 3: 1 Running total is now 21 You win and probably had help from another computer!! Computer wins 0 games, human wins 1 game Another game (y/n)? y Start game 2 ROUND 1: Your choice among 1, 2 or 3: 3 Running total is now 3 The computer chooses 1 Running total is now 4 ROUND 2: Your choice among 1, 2 or 3: 3 Running total is now 7 The computer chooses 3 Running total is now 10 ROUND 3: Your choice among 1, 2 or 3: 3 Running total is now 13 The computer chooses 2 Running total is now 15 ROUND 4: Your choice among 1, 2 or 3: 2 Running total is now 17 The computer chooses 1 Running total is now 18 ROUND 5: Your choice among 1, 2 or 3: 3 Running total is now 21 You win and probably had help from another computer!! Computer wins 0 games, human wins 2 games Another game (y/n)? y Start game 3 ROUND 1: Your choice among 1, 2 or 3: 3 Running total is now 3 The computer chooses 3 Running total is now 6 ROUND 2: Your choice among 1, 2 or 3: 3 Running total is now 9 The computer chooses 2 Running total is now 11 ROUND 3: Your choice among 1, 2 or 3: 3 Running total is now 14 The computer chooses 2 Running total is now 16 ROUND 4: Your choice among 1, 2 or 3: 3 Running total is now 19 The computer chooses 2 Running total is now 21 Computer wins!! Computer wins 1 game, human wins 2 games Another game (y/n)? n Quitting.
JavaScript
The solution as a Javascript script inside a page written in HTML5. It should work with all modern browsers. <lang javascript><!DOCTYPE html><html lang="en">
<head>
<meta charset="UTF-8">
<meta name="keywords" content="Game 21">
<meta name="description" content="
21 is a two player game, the game is played by choosing a number
(1, 2, or 3) to be added to the running total. The game is won by
the player whose chosen number causes the running total to reach
exactly 21. The running total starts at zero.
">
<meta name="dc.publisher" content="Rosseta Code">
<meta name="dc.date" content="2020-07-23">
<meta name="dc.created" content="2020-07-23">
<meta name="dc.modified" content="2020-07-30">
<title>
21 Game
</title>
<meta http-equiv="cache-control" content="no-cache">
<style>
.ui div { width: 50%; display: inline-flex; justify-content: flex-end; }
div.total { margin-bottom: 1ch; }
label { padding-right: 1ch; }
button + button { margin-left: 1em; }
</style>
</head>
<body>
21 Game in ECMA Script (Java Script)
21 is a two player game, the game is played by choosing a number (1, 2, or 3) to be added to the running total. The game is won by the player whose chosen number causes the running total to reach exactly 21. The running total starts at zero.
Use buttons to play.
<label for="human">human last choice:</label>
<input type="text" id="human" readonly>
<label for="AI">AI last choice:</label>
<input type="text" id="AI" readonly>
<label for="runningTotalText">running total:</label>
<input type="text" id="runningTotalText" readonly>
<noscript> No script, no fun. Turn on Javascript on. </noscript>
<script>
// I really dislike global variables, but in any (?) WWW browser the global
// variables are in the window (separately for each tab) context space.
//
var runningTotal = 0;
const human = document.getElementById('human');
const AI = document.getElementById('AI');
const runningTotalText = document.getElementById('runningTotalText');
const first = document.getElementById('first')
const message = document.getElementById('message');
const choiceButtons = new Array(3);
// An function to restart game in any time, should be called as a callback
// from the WWW page, see above for an example.
//
function restart()
{
runningTotal = 0;
runningTotalText.value = runningTotal;
human.value = ;
AI.value = ;
for (let i = 1; i <= 3; i++)
{
let button = document.getElementById('choice' + i);
button.disabled = false;
choiceButtons[i] = button;
}
message.innerText = ;
if (Math.random() > 0.5)
{
update(AI, ai());
first.innerText = 'The first move is AI move.'
}
else
first.innerText = 'The first move is human move.'
}
// This function update an (read-only for a user) two text boxes
// as well as runningTotal. It should be called only once per a move/turn.
//
function update(textBox, n)
{
textBox.value = n;
runningTotal = runningTotal + n;
runningTotalText.value = runningTotal;
for (let i = 1; i <= 3; i++)
if (runningTotal + i > 21)
choiceButtons[i].disabled = true;
}
// An callback function called when the human player click the button.
//
function choice(n)
{
update(human, n);
if (runningTotal == 21)
message.innerText = 'The winner is human.';
else
{
update(AI, ai());
if (runningTotal == 21)
message.innerText = 'The winner is AI.';
}
}
// A rather simple function to calculate a computer move for the given total.
//
function ai()
{
for (let i = 1; i <= 3; i++)
if (runningTotal + i == 21)
return i;
for (let i = 1; i <= 3; i++)
if ((runningTotal + i - 1) % 4 == 0)
return i;
return 1; }
// Run the script - actually this part do only some initialization, because // the game is interactively driven by events from an UI written in HTML. // restart(); </script>
</body> </html></lang>
Julia
The computer or player can always win if they go first and choose a number that brings the total to one of the following: 1, 5, 9, 13, or 17. To make things vary more, there is a choice of computer play level at the start. The computer will randomly respond with level 1 and choose a random response 1/4 of the time at level 2. <lang julia> function trytowin(n)
if 21 - n < 4
println("Computer chooses $(21 - n) and wins. GG!")
exit(0)
end
end
function choosewisely(n)
trytowin(n)
targets = [1, 5, 9, 13, 17, 21]
pos = findfirst(x -> x > n, targets)
bestmove = targets[pos] - n
if bestmove > 3
println("Looks like I could lose. Choosing a 1, total now $(n + 1).")
return n + 1
end
println("On a roll, choosing a $bestmove, total now $(n + bestmove).")
n + bestmove
end
function choosefoolishly(n)
trytowin(n)
move = rand([1, 2, 3])
println("Here goes, choosing $move, total now $(n + move).")
n + move
end
function choosesemiwisely(n)
trytowin(n)
if rand() > 0.75
choosefoolishly(n)
else
choosewisely(n)
end
end
prompt(s) = (println(s, ": => "); return readline())
function playermove(n)
rang = (n > 19) ? "1 is all" : ((n > 18) ? "1 or 2" : "1, 2 or 3")
choice = 0
while true
nstr = prompt("Your choice ($rang), 0 to exit")
if nstr == "0"
exit(0)
elseif nstr == "1"
return n + 1
elseif nstr == "2" && n < 20
return n + 2
elseif nstr == "3" && n < 19
return n + 3
end
end
end
function play21game()
n = 0
level = prompt("Level of play (1=dumb, 3=smart)")
algo = choosewisely
if level == "1"
algo = choosefoolishly
elseif level == "2"
algo = choosesemiwisely
elseif level != "3"
println("Bad choice syntax--default to smart choice")
end
whofirst = prompt("Does computer go first? (y or n)")
if whofirst[1] == 'y' || whofirst[1] == 'Y'
n = algo(n)
end
while n < 21
n = playermove(n)
if n == 21
println("Player wins! Game over, gg!")
break
end
n = algo(n)
end
end
play21game() </lang>
Lua
<lang lua> gamewon = false running_total = 0 player = 1 opponent = 2
while not gamewon do
num = 0
if player == 1 then
opponent = 2
repeat
print("Enter a number between 1 and 3 (0 to quit):")
num = io.read("*n")
if num == 0 then
os.exit()
end
until (num > 0) and (num <=3)
end
if player == 2 and not (gamewon) then
opponent = 1
if (21 - running_total <= 3) then
num = 21 - running_total
else
num = math.random(1,3)
end
print("Player 2 picks number "..num)
end
running_total = running_total + num
print("Total: "..running_total)
if running_total == 21 then
print("Player "..player.." wins!")
gamewon = true
end
if running_total > 21 then
print("Player "..player.." lost...")
print("Player "..opponent.." wins!")
gamewon = true
end
if player == 1 then
player = 2
else player = 1
end
end </lang>
Objeck
<lang objeck>class TwentyOne {
@quit : Bool; @player_total : Int; @computer_total : Int;
function : Main(args : String[]) ~ Nil {
TwentyOne->New()->Play();
}
New() {
}
method : Play() ~ Nil {
player_first := Int->Random(1) = 1;
"Enter 'q' to quit\n==="->PrintLine();
do {
if(player_first) {
PlayerTurn();
if(<>@quit) {
"---"->PrintLine();
ComputerTurn();
};
}
else {
ComputerTurn();
"---"->PrintLine();
PlayerTurn();
};
"==="->PrintLine();
}
while(<>@quit);
}
method : ComputerTurn() ~ Nil {
input := Int->Random(1, 3);
"Computer choose: {$input}"->PrintLine();
@computer_total += input;
if(@computer_total = 21) {
"Computer Wins!"->PrintLine();
@quit := true;
}
else if(@computer_total > 21) {
"Computer Loses."->PrintLine();
@quit := true;
}
else {
"Computer total is {$@computer_total}."->PrintLine();
};
}
method : PlayerTurn() ~ Nil {
input := GetInput();
if(input = -1) {
"Quit"->PrintLine();
@quit := true;
}
else if(input = 0) {
"Invalid Input!"->PrintLine();
}
else {
@player_total += input;
};
if(@player_total = 21) {
"Player Wins!"->PrintLine();
@quit := true;
}
else if(@player_total > 21) {
"Player Loses."->PrintLine();
@quit := true;
}
else {
"Player total is {$@player_total}."->PrintLine();
};
}
function : GetInput() ~ Int {
"Choosing a number beween 1-3: "->Print();
input := System.IO.Console->ReadString();
if(input->Size() = 1) {
if(input->Get(0) = 'q') {
return -1;
};
return input->ToInt(); };
return 0; }
}</lang>
Pascal
<lang pascal> program Game21;
{$APPTYPE CONSOLE}
{$R *.res}
uses
System.SysUtils, System.StrUtils, // for IfThen Winapi.Windows; // for ClearScreen
const
HARD_MODE = True;
var
computerPlayer: string = 'Computer'; humanPlayer: string = 'Player 1';
// for change color ConOut: THandle; BufInfo: TConsoleScreenBufferInfo;
procedure ClearScreen; var
stdout: THandle; csbi: TConsoleScreenBufferInfo; ConsoleSize: DWORD; NumWritten: DWORD; Origin: TCoord;
begin
stdout := GetStdHandle(STD_OUTPUT_HANDLE); Win32Check(stdout <> INVALID_HANDLE_VALUE); Win32Check(GetConsoleScreenBufferInfo(stdout, csbi)); ConsoleSize := csbi.dwSize.X * csbi.dwSize.Y; Origin.X := 0; Origin.Y := 0; Win32Check(FillConsoleOutputCharacter(stdout, ' ', ConsoleSize, Origin, NumWritten)); Win32Check(FillConsoleOutputAttribute(stdout, csbi.wAttributes, ConsoleSize, Origin, NumWritten)); Win32Check(SetConsoleCursorPosition(stdout, Origin));
end;
procedure ResetColor; begin
SetConsoleTextAttribute(ConOut, BufInfo.wAttributes);
end;
procedure ChangeColor(color: Word); begin
ConOut := TTextRec(Output).Handle; GetConsoleScreenBufferInfo(ConOut, BufInfo); SetConsoleTextAttribute(TTextRec(Output).Handle, color);
end;
function SwapPlayer(currentPlayer: string): string; begin
Result := IfThen(currentPlayer = humanPlayer, computerPlayer, humanPlayer);
end;
function RandomPlayerSelect(): string; begin
Result := IfThen(Random() < 0.5, computerPlayer, humanPlayer);
end;
function CheckIfCanWin(total: Integer): Boolean; begin
result := (total >= 18);
end;
function CheckIfCanLose(total: Integer; var choose: Integer; hardMode: Boolean =
False): Boolean;
var
range: Integer;
begin
range := 17 - total;
Result := false;
if (range > 0) and (range < 4) then
begin
Result := true;
if hardMode then
choose := range
else
choose := Random(range - 1) + 1;
end;
end;
function CompMove(total: Integer): Integer; begin
if (CheckIfCanWin(total)) then begin exit(21 - total); end;
if CheckIfCanLose(total, Result, HARD_MODE) then exit;
Result := Random(3) + 1;
end;
function HumanMove: Integer; var
choice: string;
begin
repeat
Writeln('Choose from numbers: 1, 2, 3');
Readln(choice);
until TryStrToInt(choice, Result) and (Result in [1..3]);
end;
procedure PlayGame(); var
playAnother: Boolean; total, final_, roundChoice, compWins, humanWins: Integer; choice, currentPlayer: string;
begin
playAnother := True; total := 0; final_ := 21; roundChoice := 0; Randomize; currentPlayer := RandomPLayerSelect(); compWins := 0; humanWins := 0;
while (playAnother) do begin ClearScreen; ChangeColor(FOREGROUND_INTENSITY or FOREGROUND_GREEN); Writeln(total); ResetColor; Writeln();
Writeln('Now playing: ' + currentPlayer);
if currentPlayer = computerPlayer then
roundChoice := CompMove(total)
else
roundChoice := HumanMove;
inc(total, roundChoice);
if (total = final_) then
begin
if (currentPlayer = computerPlayer) then
begin
inc(compWins);
end
else
begin
inc(humanWins);
end;
ClearScreen;
Writeln('Winner: ' + currentPlayer);
Writeln('Comp wins: ', compWins, '. Human wins: ', humanWins, #10);
Writeln('Do you wan to play another round? y/n');
readln(choice);
if choice = 'y' then
begin
total := 0;
ClearScreen;
end
else if choice = 'n' then
playAnother := false
else
begin
Writeln('Invalid choice! Choose from y or n');
Continue;
end;
end
else if total > 21 then
begin
Writeln('Not the right time to play this game :)');
break;
end;
currentPlayer := SwapPlayer(currentPlayer); end;
end;
const
WELLCOME_MSG: array[0..5] of string = ('Welcome to 21 game'#10,
'21 is a two player game.', 'The game is played by choosing a number.',
'1, 2, or 3 to be added a total sum.'#10,
'The game is won by the player reaches exactly 21.'#10, 'Press ENTER to start!'#10);
var
i: Integer;
begin
try
for i := 0 to High(WELLCOME_MSG) do
Writeln(WELLCOME_MSG[i]);
ResetColor;
Readln; // Wait press enter
PlayGame();
except
on E: Exception do
Writeln(E.ClassName, ': ', E.Message);
end;
end. </lang>
Perl
<lang perl>print <<'HERE'; The 21 game. Each player chooses to add 1, 2, or 3 to a running total. The player whose turn it is when the total reaches 21 wins. Enter q to quit. HERE
my $total = 0;
while () {
print "Running total is: $total\n";
my ($me,$comp);
while () {
print 'What number do you play> ';
$me = <>; chomp $me;
last if $me =~ /^[123]$/;
insult($me);
}
$total += $me;
win('Human') if $total >= 21;
print "Computer plays: " . ($comp = 1+int(rand(3))) . "\n";
$total += $comp;
win('Computer') if $total >= 21;
}
sub win {
my($player) = @_; print "$player wins.\n"; exit;
}
sub insult {
my($g) = @_;
exit if $g =~ /q/i;
my @insults = ('Yo mama', 'Jeez', 'Ummmm', 'Grow up');
my $i = $insults[1+int rand($#insults)];
print "$i, $g is not an integer between 1 and 3...\n"
}</lang>
- Output:
The 21 game. Each player chooses to add 1, 2, or 3 to a running total. The player whose turn it is when the total reaches 21 wins. Enter q to quit. Running total is: 0 What number do you play> 3 Computer plays: 3 Running total is: 6 What number do you play> 3 Computer plays: 3 Running total is: 12 What number do you play> 3 Computer plays: 2 Running total is: 17 What number do you play> 1 Computer plays: 1 Running total is: 19 What number do you play> 2 Human wins.
Phix
If the computer goes first you cannot win.
Once the computer stops displaying "no clear strategy" you cannot win.
The computer_first flag only applies to the first game. After winning, losing, or conceding, you go first.
<lang Phix>bool computer_first = false
bool show_spoiler = false
integer total = 0
procedure computer_play()
integer move = 0
for i=1 to 3 do
if mod(total+i,4)=1 then
move = i
exit
end if
end for
if move=0 then
puts(1,"no clear strategy\n")
move = rand(min(3,21-total))
end if
printf(1,"Total is %d. I play %d.\n",{total,move})
total += move
if total=21 then
puts(1,"21! I win!\n")
end if
end procedure
puts(1,"\n21 game\n\n") puts(1,"Press escape or q to quit the game, c to concede and start a new game from 0\n\n")
if computer_first then
printf(1,"Total is %d.\n",{total})
computer_play()
elsif show_spoiler then
-- The secret to winning!
puts(1,sq_sub("Uif!pomz!xbz!up!xjo!jt!qmbz!2!gjstu-!uifo!5.=dpnqvufs!npwf?!fwfsz!ujnf",1)&"\n\n")
end if
while 1 do
printf(1,"Total is %d. enter 1, 2, or 3: ",{total})
integer ch = wait_key()
puts(1,iff(ch=#1B?"esc":ch)&"\n")
if ch>='1' and ch<='3' then
ch -= '0'
if total+ch>21 then
puts(1,"Too big\n")
else
total += ch
if total=21 then
puts(1,"21! You win!\n")
else
computer_play()
end if
end if
elsif ch=#1B or lower(ch)='q' then
puts(1,"Quitting\n")
exit
end if
if lower(ch)='c' or total=21 then
total = 0
end if
end while</lang>
- Output:
21 game Press escape or q to quit the game, c to concede and start a new game from 0 Total is 0. enter 1, 2, or 3: 1 no clear strategy Total is 1. I play 3. Total is 4. enter 1, 2, or 3: 1 no clear strategy Total is 5. I play 1. Total is 6. enter 1, 2, or 3: 3 no clear strategy Total is 9. I play 1. Total is 10. enter 1, 2, or 3: 1 Total is 11. I play 2. Total is 13. enter 1, 2, or 3: 3 Total is 16. I play 1. Total is 17. enter 1, 2, or 3: 2 Total is 19. I play 2. 21! I win! Total is 0. enter 1, 2, or 3: q Quitting
PHP
The solution as a server-side PHP7 script and HTML5. <lang PHP><!DOCTYPE html> <html lang="en">
<head>
<meta charset="UTF-8">
<meta name="keywords" content="Game 21">
<meta name="description" content="
21 is a two player game, the game is played by choosing a number
(1, 2, or 3) to be added to the running total. The game is won by
the player whose chosen number causes the running total to reach
exactly 21. The running total starts at zero.
">
<meta name="dc.publisher" content="Rosseta Code">
<meta name="dc.date" content="2020-07-31">
<meta name="dc.created" content="2020-07-31">
<meta name="dc.modified" content="2020-08-01">
<title>
21 Game
</title>
<meta http-equiv="cache-control" content="no-cache">
<style>
.ui div { width: 50%; display: inline-flex; justify-content: flex-end; }
div.total { margin-bottom: 1ch; }
label { padding-right: 1ch; }
button + button { margin-left: 1em; }
</style>
</head>
<body>
21 Game in PHP 7
21 is a two player game, the game is played by choosing a number (1, 2, or 3) to be added to the running total. The game is won by the player whose chosen number causes the running total to reach exactly 21. The running total starts at zero.
<?php
const GOAL = 21;
const PLAYERS = array('AI', 'human');
function best_move($n)
{
for ($i = 1; $i <= 3; $i++)
if ($n + $i == GOAL)
return $i;
for ($i = 1; $i <= 3; $i++)
if (($n + $i - 1) % 4 == 0)
return $i;
return 1;
}
if (isset($_GET['reset']) || !isset($_GET['total']))
{
$first = PLAYERS[rand(0, 1)];
$total = 0;
$human = 0;
$ai = 0;
$message = ;
if ($first == 'AI')
{
$move = best_move($total);
$ai = $move;
$total = $total + $move;
}
}
else
{
$first = $_GET['first'];
$total = $_GET['total'];
$human = $_GET['human'];
$ai = $_GET['ai'];
$message = $_GET['message'];
}
if (isset($_GET['move']))
{
$move = (int)$_GET['move'];
$human = $move;
$total = $total + $move;
if ($total == GOAL)
$message = 'The winner is human.';
else
{
$move = best_move($total);
$ai = $move;
$total = $total + $move;
if ($total == GOAL)
$message = 'The winner is AI.';
}
}
$state = array();
for ($i = 1; $i <= 3; $i++)
$state[$i] = $total + $i > GOAL ? 'disabled' : ;
echo <<< END
The first player is $first. Use buttons to play.
<form class="ui">
<input type='hidden' id='first' name='first' value='$first'>
<input type='hidden' name='message' value='$message'>
<label for='human'>human last choice:</label>
<input type='text' name='human' readonly value='$human'>
<label for='AI'>AI last choice:</label>
<input type='text' name='ai' readonly value='$ai'>
<label for='runningTotalText'>running total:</label>
<input type='text' name='total' readonly value='$total'>
</form>
$message
END ?>
</body></lang>
Python
<lang python> from random import randint def start(): game_count=0 print("Enter q to quit at any time.\nThe computer will choose first.\nRunning total is now {}".format(game_count)) roundno=1 while game_count<21: print("\nROUND {}: \n".format(roundno)) t = select_count(game_count) game_count = game_count+t print("Running total is now {}\n".format(game_count)) if game_count>=21: print("So, commiserations, the computer has won!") return 0 t = request_count() if not t: print('OK,quitting the game') return -1 game_count = game_count+t print("Running total is now {}\n".format(game_count)) if game_count>=21: print("So, congratulations, you've won!") return 1 roundno+=1
def select_count(game_count): selects a random number if the game_count is less than 18. otherwise chooses the winning number if game_count<18: t= randint(1,3) else: t = 21-game_count print("The computer chooses {}".format(t)) return t
def request_count(): request user input between 1,2 and 3. It will continue till either quit(q) or one of those numbers is requested. t="" while True: try: t = raw_input('Your choice 1 to 3 :') if int(t) in [1,2,3]: return int(t) else: print("Out of range, try again") except: if t=="q": return None else: print("Invalid Entry, try again")
c=0 m=0 r=True while r: o = start() if o==-1: break else: c+=1 if o==0 else 0 m+=1 if o==1 else 0 print("Computer wins {0} game, human wins {1} games".format(c,m)) t = raw_input("Another game?(press y to continue):") r = (t=="y")</lang>
- Output:
Enter q to quit at any time. The computer will choose first. Running total is now 0 ROUND 1: The computer chooses 1 Running total is now 1 Your choice 1 to 3 :4 Out of range, try again Your choice 1 to 3 :w Invalid Entry, try again Your choice 1 to 3 :3 Running total is now 4 ROUND 2: The computer chooses 1 Running total is now 5 Your choice 1 to 3 :2 Running total is now 7 ROUND 3: The computer chooses 3 Running total is now 10 Your choice 1 to 3 :3 Running total is now 13 ROUND 4: The computer chooses 1 Running total is now 14 Your choice 1 to 3 :2 Running total is now 16 ROUND 5: The computer chooses 1 Running total is now 17 Your choice 1 to 3 :1 Running total is now 18 ROUND 6: The computer chooses 3 Running total is now 21 So, commiserations, the computer has won! Computer wins 1 game, human wins 0 games Another game?(press y to continue):y Enter q to quit at any time. The computer will choose first. Running total is now 0 ROUND 1: The computer chooses 1 Running total is now 1 Your choice 1 to 3 :3 Running total is now 4 ROUND 2: The computer chooses 3 Running total is now 7 Your choice 1 to 3 :3 Running total is now 10 ROUND 3: The computer chooses 3 Running total is now 13 Your choice 1 to 3 :5 Out of range, try again Your choice 1 to 3 :3 Running total is now 16 ROUND 4: The computer chooses 2 Running total is now 18 Your choice 1 to 3 :3 Running total is now 21 So, congratulations, you've won! Computer wins 1 game, human wins 1 games Another game?(press y to continue):y Enter q to quit at any time. The computer will choose first. Running total is now 0 ROUND 1: The computer chooses 3 Running total is now 3 Your choice 1 to 3 :4 Out of range, try again Your choice 1 to 3 :3 Running total is now 6 ROUND 2: The computer chooses 3 Running total is now 9 Your choice 1 to 3 :q OK,quitting the game
Racket
<lang racket>#lang racket
(define limit 21) (define max-resp 3)
(define (get-resp)
(let loop ()
(match (read-line)
[(app (conjoin string? string->number) n)
#:when (and (exact-integer? n) (<= 1 n max-resp))
n]
["q" (exit)]
[n (printf "~a is not in range 1 and ~a\n" n max-resp)
(loop)])))
(define (win human?) (printf "~a wins\n" (if human? "Human" "Computer")))
(printf "The ~a game. Each player chooses to add a number in range 1 and ~a to a running total. The player whose turn it is when the total reaches exactly ~a wins. Enter q to quit.\n\n" limit max-resp limit)
(let loop ([total 0] [human-turn? (= 0 (random 2))])
(define new-total
(+ total
(cond
[human-turn? (printf "Running total is: ~a\n" total)
(printf "Your turn:\n")
(get-resp)]
[else (define resp (random 1 (add1 max-resp)))
(printf "Computer plays: ~a\n" resp)
resp])))
(cond
[(= new-total limit) (win human-turn?)]
[(> new-total limit) (win (not human-turn?))]
[else (loop new-total (not human-turn?))]))</lang>
- Output:
The 21 game. Each player chooses to add an integer in range 1 and 3 to a running total. The player whose turn it is when the total reaches exactly 21 wins. Enter q to quit. Running total is: 0 Your turn: 1 Computer plays: 3 Running total is: 4 Your turn: foo foo is not an integer in range 1 and 3 Your turn: bar bar is not an integer in range 1 and 3 Your turn: 3 Computer plays: 1 Running total is: 8 Your turn: 1 Computer plays: 1 Running total is: 10 Your turn: 1 Computer plays: 2 Running total is: 13 Your turn: 1 Computer plays: 3 Running total is: 17 Your turn: 1 Computer plays: 2 Running total is: 20 Your turn: 1 Human wins
Raku
(formerly Perl 6)
Since there is no requirement that the computer play sensibly, it always plays a random guess so the player has some chance to win. <lang perl6>say qq :to 'HERE';
The 21 game. Each player chooses to add 1, 2, or 3 to a running total. The player whose turn it is when the total reaches 21 wins. Enter q to quit. HERE
my $total = 0; loop {
say "Running total is: $total";
my ($me,$comp);
loop {
$me = prompt 'What number do you play> ';
last if $me ~~ /^<[123]>$/;
insult $me;
}
$total += $me;
win('Human') if $total >= 21;
say "Computer plays: { $comp = (1,2,3).roll }\n";
$total += $comp;
win('Computer') if $total >= 21;
}
sub win ($player) {
say "$player wins."; exit;
}
sub insult ($g) {
exit if $g eq 'q';
print ('Yo mama,', 'Jeez,', 'Ummmm,', 'Grow up,', 'Did you even READ the instructions?').roll;
say " $g is not an integer between 1 & 3..."
}</lang>
- Sample game:
The 21 game. Each player chooses to add 1, 2, or 3 to a running total. The player whose turn it is when the total reaches 21 wins. Enter q to quit. Running total is: 0 What number do you play> 5 Did you even READ the instructions? 5 is not an integer between 1 & 3... What number do you play> g Yo mama, g is not an integer between 1 & 3... What number do you play> 12 Jeez, 12 is not an integer between 1 & 3... What number do you play> 3 Computer plays: 2 Running total is: 5 What number do you play> 3 Computer plays: 3 Running total is: 11 What number do you play> 1 Computer plays: 1 Running total is: 13 What number do you play> 3 Computer plays: 2 Running total is: 18 What number do you play> 3 Human wins.
REXX
Around half of the REXX program deals with incorrect or missing input (of the required integer).
This REXX version allows the user to choose if the computer should go first. <lang rexx>/*REXX program plays the 21 game with a human, each player chooses 1, 2, or 3 which */ /*──────────── is added to the current sum, the first player to reach 21 exactly wins.*/ sep= copies('─', 8); sep2= " "copies('═', 8)" " /*construct an eye─catching msg fences.*/ say sep 'Playing the 21 game.' /*tell what's happening here at the zoo*/ $=0; goal= 21 /*the sum [or running total] (so far).*/
do j=1 while $<goal; call g /*obtain the user's number via a prompt*/ if x\==0 then call tot x, 1 /*Not 0? The user wants to go first. */ if $==goal then leave /*the user won the game with the last #*/ call ?; if y==. then y= random(1, 3) /*get computer's choice or a random #*/ say sep 'The computer chooses ' y " as it's choice." /*inform player.*/ call tot y, 0 /*call subroutine to show the total. */ end /*j*/
say if who then say sep 'Congratulations! You have won the 21 game.'
else say sep 'The computer has won the 21 game.'
exit 0 /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ ?: y=.; do c=1 for 3 until y\==.; if (c+$) // 4 == 1 then y= c; end; return ser: if bad then return; bad=1; say; say; say sep '***error***' arg(1); say; return tot: arg q,who; $=$+q; say sep 'The game total is now' sep2 $ sep2; /*add; show $*/ return /*──────────────────────────────────────────────────────────────────────────────────────*/ g: low = (j \== 1) /*allow user to have computer go first.*/
do until \bad; bad= 0; say /*prompt 'til user gives a good number.*/
say sep 'Please enter a number from ' low " ───► 3 (or Quit):"
if j=1 then say sep '[A value of 0 (zero) means you want the computer to go first.]'
parse pull x _ . 1 ox; upper x /*obtain user's lowercase response(s). */
if x= then call ser "Nothing entered."
if _\== then call ser "Too many arguments entered: " ox
if abbrev('QUIT', x, 1) then do; say; say sep "quitting."; exit 1; end
if \datatype(x, 'N') then call ser "Argument isn't numeric: " ox
if \datatype(x, 'W') then call ser "Number isn't an integer: " ox
if x<0 then call ser "Number can't be negative: " x
if x=0 & j>1 then call ser "Number can't be zero: " x
if x>3 then call ser "Number is too large (>3): " x
if bad then iterate /*Had an error? Then get another number*/
x= x/1; if $+x>goal then call ser "Number will cause the sum to exceed " goal': ' x
end /*until*/; return</lang>
- output :
──────── Playing the 21 game. ──────── Please enter a number from 0 ───► 3 (or Quit): ──────── [A value of 0 (zero) means you want the computer to go first.] 3 ◄■■■■■■■■■■ user input ──────── The game total is now ════════ 3 ════════ ──────── The computer chooses 2 as it's choice. ──────── The game total is now ════════ 5 ════════ ──────── Please enter a number from 1 ───► 3 (or Quit): 3 ◄■■■■■■■■■■ user input ──────── The game total is now ════════ 8 ════════ ──────── The computer chooses 1 as it's choice. ──────── The game total is now ════════ 9 ════════ ──────── Please enter a number from 1 ───► 3 (or Quit): 3 ◄■■■■■■■■■■ user input ──────── The game total is now ════════ 12 ════════ ──────── The computer chooses 1 as it's choice. ──────── The game total is now ════════ 13 ════════ ──────── Please enter a number from 1 ───► 3 (or Quit): 3 ◄■■■■■■■■■■ user input ──────── The game total is now ════════ 16 ════════ ──────── The computer chooses 1 as it's choice. ──────── The game total is now ════════ 17 ════════ ──────── Please enter a number from 1 ───► 3 (or Quit): 1 ◄■■■■■■■■■■ user input ──────── The game total is now ════════ 18 ════════ ──────── The computer chooses 3 as it's choice. ──────── The game total is now ════════ 21 ════════ ──────── The computer has won the 21 game.
Ring
<lang ring>
- Project : 21 Game
load "guilib.ring"
limit = 21 posold = 0 button = list(limit) mynum = list(3) yournum = list(3)
new qapp
{
win1 = new qwidget() {
setwindowtitle("21 Game")
setgeometry(100,100,1000,600)
label1 = new qlabel(win1) {
setgeometry(10,10,1000,600)
settext("")
}
label2 = new qlabel(win1) {
setgeometry(240,50,120,40)
setAlignment(Qt_AlignHCenter)
setFont(new qFont("Verdana",12,100,0))
settext("my number:")
}
label3 = new qlabel(win1) {
setgeometry(640,50,120,40)
setAlignment(Qt_AlignHCenter)
setFont(new qFont("Verdana",12,100,0))
settext("your number:")
}
for p = 1 to 3
mynum[p] = new qpushbutton(win1) {
setgeometry(200+p*40,100,40,40)
setstylesheet("background-color:orange")
settext(string(p))
setclickevent("choose(" + string(p) + ",1)")
}
next
for p = 1 to 3
yournum[p] = new qpushbutton(win1) {
setgeometry(600+p*40,100,40,40)
setstylesheet("background-color:white")
settext(string(p))
setclickevent("choose(" + string(p) + ",2)")
}
next
for n = 1 to limit
button[n] = new qpushbutton(win1) {
setgeometry(40+n*40,190,40,40)
settext(string(n))
}
next
show()
}
exec()
}
func choose(ch,ym)
pos = posold + ch
if pos > limit
msg = "You must choose number from 1 to " + string(limit - posold)
msgBox(msg)
for n = 1 to 3
mynum[n].setenabled(false)
yournum[n].setenabled(false)
next
return
ok
for n = posold+1 to pos
if ym = 1
button[n] { setstylesheet("background-color:orange") }
else
button[n] { setstylesheet("background-color:white") }
ok
next
posold = pos
if ym = 1
for n = 1 to 3
mynum[n].setenabled(false)
yournum[n].setenabled(true)
next
else
for n = 1 to 3
mynum[n].setenabled(true)
yournum[n].setenabled(false)
next
ok
if pos = 21
if ym = 1
msgBox("I won!")
else
msgBox("You won!")
ok
ok
func msgBox(text) { m = new qMessageBox(win1) { setWindowTitle("21 Game") setText(text) show() }
}
</lang>
Output:
21 Game
Ruby
<lang Ruby>
- 21 Game - an example in Ruby for Rosetta Code.
GOAL = 21 MIN_MOVE = 1 MAX_MOVE = 3
DESCRIPTION = "
- Welcome to the 21 Game! ***
21 is a two player game. Each player chooses to add 1, 2 or 3 to a running total. The player whose turn it is when the total reaches 21 will win the game. The running total starts at zero.
The players start the game in turn. Enter q to quit at any time. "
- Returns the best move to play.
def best_move(total)
move = rand(1..3) MIN_MOVE.upto(MAX_MOVE) do |i| move = i if (total + i - 1) % (MAX_MOVE + 1) == 0 end MIN_MOVE.upto(MAX_MOVE) do |i| move = i if total + i == GOAL end move
end
- Gets the move of the player.
def get_move
print "Your choice between #{MIN_MOVE} and #{MAX_MOVE}: "
answer = gets
move = answer.to_i
until move.between?(MIN_MOVE, MAX_MOVE)
exit if answer.chomp == 'q'
print 'Invalid choice. Try again: '
answer = gets
move = answer.to_i
end
move
end
- Asks the player to restart a game and returns the answer.
def restart?
print 'Do you want to restart (y/n)? ' restart = gets.chomp until ['y', 'n'].include?(restart) print 'Your answer is not a valid choice. Try again: ' restart = gets.chomp end restart == 'y'
end
- Run a game. The +player+ argument is the player that starts:
- * 1 for human
- * 0 for computer
def game(player)
total = round = 0
while total < GOAL
round += 1
puts "--- ROUND #{round} ---\n\n"
player = (player + 1) % 2
if player == 0
move = best_move(total)
puts "The computer chooses #{move}."
else
move = get_move
end
total += move
puts "Running total is now #{total}.\n\n"
end
if player == 0
puts 'Sorry, the computer has won!'
return false
end
puts 'Well done, you have won!'
true
end
- MAIN
puts DESCRIPTION run = true computer_wins = human_wins = 0 games_counter = player = 1 while run
puts "\n=== START GAME #{games_counter} ==="
player = (player + 1) % 2
if game(player)
human_wins += 1
else
computer_wins += 1
end
puts "\nComputer wins #{computer_wins} games, you wins #{human_wins} game."
games_counter += 1
run = restart?
end puts 'Good bye!' </lang>
rust
<lang rust>use rand::Rng; use std::io;
- [derive(Clone)]
enum PlayerType {
Human, Computer,
}
- [derive(Clone)]
struct Player {
name: String, wins: u32, // holds wins level: u32, // difficulty level of Computer player_type: PlayerType,
}
trait Choose {
fn choose(&self, game: &Game) -> u8;
}
impl Player {
fn new(name: &str, player_type: PlayerType, level: u32) -> Player {
Player {
name: String::from(name),
wins: 0,
level,
player_type,
}
}
fn get_name(&self) -> &str {
&self.name[..]
}
fn get_level(&self) -> u32 {
self.level
}
fn add_win(&mut self) {
self.wins += 1
}
fn level_up(&mut self) {
self.level += 1
}
}
impl Choose for Player {
fn choose(&self, game: &Game) -> u8 {
match self.player_type {
PlayerType::Human => loop {
let max_choice = game.max_choice();
match max_choice {
1 => println!("Enter a number 1 to win (or quit):"),
_ => println!("Enter a number between 1 and {} (or quit):", max_choice)
}
let mut guess = String::new();
io::stdin()
.read_line(&mut guess)
.expect("Failed to read line");
if guess.trim() == "quit" {
return 0
}
let guess: u8 = match guess.trim().parse() {
Ok(num) if num >= 1 && num <= max_choice => num,
Ok(_) => continue,
Err(_) => continue,
};
return guess;
},
PlayerType::Computer => match self.level {
5 => match game.get_total() {
total if total == 20 => 1,
total if total == 19 => 2,
total if total == 18 => 3,
_ => 1,
},
4 => match game.get_total() {
total if total == 20 => 1,
total if total == 19 => 2,
total if total == 18 => 3,
_ => rand::thread_rng().gen_range(1, 3),
},
3 => match game.get_total() {
total if total == 20 => 1,
total if total == 19 => 2,
total if total == 18 => 3,
_ => rand::thread_rng().gen_range(1, 4),
},
2 => match game.get_total() {
total if total == 20 => 1,
total if total == 19 => 2,
_ => rand::thread_rng().gen_range(1, 3),
},
1 => 1,
_ => match game.get_total() {
total if total == 20 => 1,
total if total == 19 => 2,
total if total == 18 => 3,
_ => match game.get_remaining() % 4 {
0 => rand::thread_rng().gen_range(1, 4),
_ => game.get_remaining() % 4,
},
},
},
}
}
}
struct Game {
players: Vec<Player>, turn: u8, total: u8, start: u8, // determines which player goes first
}
impl Game {
fn init(players: &Vec<Player>) -> Game {
Game {
players: players.to_vec(),
turn: 1,
total: 0,
start: rand::thread_rng().gen_range(0, 2),
}
}
fn play(&mut self) -> &Player {
loop {
println!(
"Total now {} (remaining: {})",
self.get_total(),
self.get_remaining()
);
{
let player = self.whose_turn();
println!("Turn: {} ({} turn)", self.get_turn(), player.get_name());
let choice = player.choose(&self);
if choice == 0 {
self.next_turn();
break; // quit
}
println!("{} choose {}", player.get_name(), choice);
self.add_total(choice)
}
if self.get_total() >= 21 {
break;
}
println!("");
self.next_turn();
}
self.whose_turn()
}
fn add_total(&mut self, choice: u8) {
self.total += choice;
}
fn next_turn(&mut self) {
self.turn += 1;
}
fn whose_turn(&self) -> &Player {
let index: usize = ((self.turn + self.start) % 2).into();
&self.players[index]
}
fn get_total(&self) -> u8 {
self.total
}
fn get_remaining(&self) -> u8 {
21 - self.total
}
fn max_choice(&self) -> u8 {
match self.get_remaining() {
1 => 1,
2 => 2,
_ => 3
}
}
fn get_turn(&self) -> u8 {
self.turn
}
}
fn main() {
let mut game_count = 0;
let mut players = vec![
Player::new("human", PlayerType::Human, 0),
Player::new("computer", PlayerType::Computer, 1),
];
println!("21 Game");
println!("Press enter key to start");
{
let _ = io::stdin().read_line(&mut String::new());
}
loop {
game_count += 1;
let mut game = Game::init(&players);
let winner = game.play();
{
let mut index = 0;
while index < players.len() {
if players[index].get_name() == winner.get_name() {
players[index].add_win();
}
index += 1
}
}
println!("\n{} won game {}\n", winner.get_name(), game_count);
// limit game count
if game_count >= 10000 {
break;
}
// ask player if they want to keep on playing
println!("Press enter key to play again (or quit):");
let mut reply = String::new();
io::stdin()
.read_line(&mut reply)
.expect("Failed to read line");
if reply.trim() == "quit" {
break;
}
// level up computer
if winner.get_name() != "computer" {
println!("Computer leveling up ...");
players[1].level_up();
println!("Computer now level {}!", players[1].get_level());
println!("Beware!\n");
}
}
println!("player: {} win: {}", players[0].get_name(), players[0].wins);
println!("player: {} win: {}", players[1].get_name(), players[1].wins);
} </lang>
Visual Basic .NET
Platform: .NET
To compile this program you need to create a Visual Basic .NET project called Game21vb in Microsoft Visual Studio and paste (removing the previous content) to the MainWindow.xaml and MainWindow.xaml.vb files the source code given below.
The file MainWindow.xaml.vb with Visual Basic source code.
<lang vbnet>' Game 21 in VB.NET - an example for Rosetta Code
Class MainWindow
Private Const GOAL As Integer = 21 Private total As Integer = 0 Private random As New Random
Private Sub Update(box As TextBox, player As String, move As Integer)
total = total + move
box.Text = move
boxTotal.Text = total
If total + 1 > GOAL Then button1.IsEnabled = False
If total + 2 > GOAL Then button2.IsEnabled = False
If total + 3 > GOAL Then button3.IsEnabled = False
If total = GOAL Then
winner.Content = $"The winner is {player}."
End If
End Sub
Private Sub Ai()
Dim move As Integer = 1
For i = 1 To 3
If (total + i - 1) Mod 4 = 0 Then move = i
Next i
For i = 1 To 3
If total + i = GOAL Then move = i
Next i
Update(boxAI, "AI", move)
End Sub
Private Sub Choice(sender As Object, e As RoutedEventArgs) _
Handles button1.Click, button2.Click, button3.Click
Update(boxHuman, "human", sender.Content)
If total < GOAL Then Ai()
End Sub
' StartGame method handles both OnLoad (WM_INIT?) event ' as well as the restart of the game after user press the 'restart' button. ' Private Sub StartGame(sender As Object, e As RoutedEventArgs) Handles restart.Click
total = 0
boxAI.Text = ""
boxHuman.Text = ""
boxTotal.Text = ""
'first.Content = "" ' It is not necessary, see below.
winner.Content = ""
button1.IsEnabled = True
button2.IsEnabled = True
button3.IsEnabled = True
' The random.Next(2) return pseudorandomly either 0 or 1. Generally
' random.Next(n) Return a value from 0 (inclusive) To n - 1 (inclusive).
'
If random.Next(2) = 0 Then
first.Content = "First player is AI player."
Ai()
Else
first.Content = "First player is human player."
End If
End Sub
End Class</lang>
The file MainWindow.xaml with GUI source code written in XAML.
<lang xml><Window x:Class="MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-namespace:Game21vb" mc:Ignorable="d" Title="Game 21" Height="292" Width="409" Loaded="StartGame"> <Grid> <TextBlock HorizontalAlignment="Left" Margin="10,10,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Height="64" Width="376"> Game 21 is a two player game, the game is played by choosing a number (1, 2, or 3) to be added to the running total. The game is won by the player whose chosen number causes the running total to reach exactly 21. The running total starts at zero. </TextBlock> <Label Content="AI" HorizontalAlignment="Left" Margin="60,121,0,0" VerticalAlignment="Top" Width="49" HorizontalContentAlignment="Right"/> <Label Content="Human" HorizontalAlignment="Left" Margin="60,152,0,0" VerticalAlignment="Top" HorizontalContentAlignment="Right"/> <Label Content="Total" HorizontalAlignment="Left" Margin="60,183,0,0" VerticalAlignment="Top" Width="49" HorizontalContentAlignment="Right"/> <TextBox x:Name="boxAI" HorizontalAlignment="Left" Height="23" Margin="114,125,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120" IsReadOnly="True"/> <TextBox x:Name="boxHuman" HorizontalAlignment="Left" Height="23" Margin="114,156,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120" IsReadOnly="True"/> <TextBox x:Name="boxTotal" HorizontalAlignment="Left" Height="23" Margin="114,187,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120" IsReadOnly="True"/> <Button x:Name="button1" Content="1" HorizontalAlignment="Left" Margin="114,220,0,0" VerticalAlignment="Top" Width="25"/> <Button x:Name="button2" Content="2" HorizontalAlignment="Left" Margin="144,220,0,0" VerticalAlignment="Top" Width="25"/> <Button x:Name="button3" Content="3" HorizontalAlignment="Left" Margin="174,220,0,0" VerticalAlignment="Top" Width="25"/> <Button x:Name="restart" Content="restart" HorizontalAlignment="Left" Margin="215,220,0,0" VerticalAlignment="Top" Width="75"/> <Label x:Name="winner" HorizontalAlignment="Left" Margin="245,184,0,0" VerticalAlignment="Top" Width="133"/> <Label x:Name="first" HorizontalAlignment="Left" Margin="10,79,0,0" VerticalAlignment="Top"/> </Grid>
</Window> </lang>