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Blackjack game #502

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9dc7bf0
ver2 blackjack
yinglingtan Feb 19, 2024
f2b1d42
vers 3 hit or stand
yinglingtan Feb 19, 2024
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349 changes: 347 additions & 2 deletions script.js
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Original file line number Diff line number Diff line change
@@ -1,4 +1,349 @@
// Blackjack Base Game Walkthrough
// 1. playable game with minimum functions: creating deck, shuffling, dealing cards, evaluating winner
// 2. ability for the player to hit or stand
// 3. ability for the dealer to hit or stand
// 4. variable value of Ace - either '1' or '11'.

// ===== ===== Pseudocode for Version 1 ===== ===== //
// 1. define player and dealer
// 2. create and shuffle a game deck
// 3. draw 2 cards for player and dealer respectively
// 4. win conditions
// -- blackjack
// -- higher hand value
// 5. display hands of both player and dealer and declare winner

// ==== ==== Pseudocode for Version 2 ==== ==== //
// 1. extra game mode "hit or stand"
// 2. functionality for user to input hit or stand.

// ===== ===== Pseudocode for Version 3 ===== ===== //
// 1. Dear to hit or stand ONLY AFTER player choose to stand
// 2. if dealer hand value is less than 17, dealer hits
// 3. if dealer hand value is more than 17, dealer stands

// ===== ===== Pseudocode for Version 4 ===== ===== //
// if totalHandValue, including an ace, is less than 21, ace value is 11
// when totalHandValue, including an ace, is more than 21, ace value is reduced to 1.

/* ================================================== */
/* =========== GLOBAL VARIABLES ======================= */
/* ================================================== */

// Declare game modes
var GAME_START = "game start";
var GAME_CARDS_DRAWN = "cards drawn";
var GAME_RESULTS_SHOWN = "results shown";
var GAME_HIT_OR_STAND = "hit or stand";
var currentGameMode = GAME_START;

// Declare variables to store player and dealer hands
// We use arrays as each hand will be holding multiple card objects
var playerHand = [];
var dealerHand = [];

// Declare variable to hold deck of cards
var gameDeck = "empty at the start";

/* ================================================== */
/* =========== DECK CREATION FUNCTIONS ============== */
/* ================================================== */

// Function that creates a deck of cards, used by createNewDeck function
var createDeck = function () {
// deck array
var deck = [];
// for 'while loop' to create suits for cards
var suits = ["Diamonds", "Clubs", "Hearts", "Spades"];
var indexSuits = 0;
while (indexSuits < suits.length) {
var currSuit = suits[indexSuits];
// 13 ranks... ace to king - rank to define "card positions"
var indexRanks = 1;
while (indexRanks <= 13) {
var cardName = indexRanks;
// define card value - differentiate from rank: 'ace' = 1 / 11, 'jack' & 'queen' & 'king' = 10
if (cardName == 1) {
cardName = "ace";
// define ace value as 11 all the way. if handValue > 10, -11 to total value
// vs. coding a function to redefine the value for ace
}
if (cardName == 11) {
cardName = "jack";
}
if (cardName == 12) {
cardName = "queen";
}
if (cardName == 13) {
cardName = "king";
}
var card = {
name: cardName,
suit: currSuit,
rank: indexRanks,
};
deck.push(card);
indexRanks = indexRanks + 1;
}
indexSuits = indexSuits + 1;
}
return deck;
};

// Function that generates a random number, used by shuffle deck function
var getRandomIndex = function (size) {
return Math.floor(Math.random() * size);
};

// Function that shuffles a deck, used by createNewDeck function
var shuffleDeck = function (cards) {
var index = 0;
while (index < cards.length) {
var randomIndex = getRandomIndex(cards.length);
var currentItem = cards[index];
var randomItem = cards[randomIndex];
cards[index] = randomItem;
cards[randomIndex] = currentItem;
index = index + 1;
}
return cards;
};

// Function that creates and shuffles a deck
var createNewDeck = function () {
var newDeck = createDeck();
var shuffledDeck = shuffleDeck(newDeck);
return shuffledDeck;
};

// Function that checks a hand for blackjack
var checkForBlackjack = function (handArray) {
// Check player hand
var playerCardOne = handArray[0];
var playerCardTwo = handArray[1];
var isBlackjack = false;

// if there is a blackjack, return true
// possible scenarios:
// 1st card ace, 2nd card 10 or picture cards
// 1st card 10 or picture cards, 2nd card, ace
if (
(playerCardOne.name == "ace" && playerCardTwo.rank >= 10) ||
(playerCardOne.rank >= 10 && playerCardTwo.name == "ace")
) {
isBlackjack = true;
}

// else return false - don't need statement because variable already set to false
return isBlackjack;
};

/* ================================================== */
/* =========== GAME FUNCTIONS ======================= */
/* ================================================== */

// Function that calculates a hand
var calculateTotalHandValue = function (handArray) {
var totalHandValue = 0;
var aceCounter = 0;

// loop through player or dealer hand and add up the values
var index = 0;
while (index < handArray.length) {
var currentCard = handArray[index];

// for jack, queen, king, value is 10
if (
currentCard.name == "jack" ||
currentCard.name == "queen" ||
currentCard.name == "king"
) {
totalHandValue = totalHandValue + 10;
} else if (currentCard.name == "ace") {
totalHandValue = totalHandValue + 11;
aceCounter = aceCounter + 1;
} else {
totalHandValue = totalHandValue + currentCard.rank;
}
index = index + 1;
}

index = 0;
while (index < aceCounter) {
if (totalHandValue > 21) {
totalHandValue = totalHandValue - 10;
}
index = index + 1;
}
return totalHandValue;
};

// Function that displays the player and dealer hands in a message
var displayPlayerAndDealers = function (playerHandArray, dealerHandArray) {
// Player hand
var playerMessage = "Player Hand: <br>";
var index = 0;
while (index < playerHandArray.length) {
playerMessage =
playerMessage +
"- " +
playerHandArray[index].name +
" of " +
playerHandArray[index].suit +
"<br>";
index = index + 1;
}

// Dealer hand
index = 0;
var dealerMessage = "Dealer Hand: <br>";
while (index < dealerHandArray.length) {
dealerMessage =
dealerMessage +
"- " +
dealerHandArray[index].name +
" of " +
dealerHandArray[index].suit +
"<br>";
index = index + 1;
}

return playerMessage + "<br>" + dealerMessage;
};

// Function that displays the total hand values of the player and the dealer in a message
var displayHandTotalValues = function (playerHandValue, dealerHandValue) {
var totalHandValueMessage = "<br>Player total hand value: " + playerHandValue;
return totalHandValueMessage;
};
/* ================================================== */
/* =========== MAIN FUNCTIONS ======================= */
/* ================================================== */

var main = function (input) {
var myOutputValue = 'hello world';
return myOutputValue;
var outputMessage = "";

// FIRST CLICK
if (currentGameMode == GAME_START) {
// Create the game deck
gameDeck = createNewDeck();

// Deal 2 cards to player and dealer respectively
playerHand.push(gameDeck.pop());
playerHand.push(gameDeck.pop());
dealerHand.push(gameDeck.pop());
dealerHand.push(gameDeck.pop());

// check player and dealer cards
console.log("player hand ==> ");
console.log(playerHand);
console.log("dealer hand ==>");
console.log(dealerHand);

// progress the gameMode
currentGameMode = GAME_CARDS_DRAWN;

// write and retrun the appropriate output message
outputMessage =
'Everyone has been dealt a card. Click "submit button to evaluate cards!';

return outputMessage;
}

// SECOND CLICK
if (currentGameMode == GAME_CARDS_DRAWN) {
// check for blackjack
var playerHasBlackjack = checkForBlackjack(playerHand);
var dealerHasBlackjack = checkForBlackjack(dealerHand);

// console.log("Does Player have Black Jack? ==>", playerHasBlackjack);
// console.log("Does Dealer have Black Jack? ==>", dealerHasBlackjack);

// Condition when either player or dealer has black jack
if (playerHasBlackjack == true || dealerHasBlackjack == true) {
// both player and dealer has blackjack -> tie
if (playerHasBlackjack == true && dealerHasBlackjack == true) {
outputMessage = "It is a blackjack tie!";
}
// only player has blackjack -> player wins
else if (playerHasBlackjack == true && dealerHasBlackjack == false) {
outputMessage = "Player wins by blackjack!";
}
// only dealer has blackjack -> dealer wins
else {
outputMessage = "Dealer wins by blackjack";
}
} else {
outputMessage = "There is no blackjack!";

// change game mode
currentGameMode = GAME_HIT_OR_STAND;
}

// appropriate output message
return outputMessage;
}

// HIT OR STAND
if (currentGameMode == GAME_HIT_OR_STAND) {
// Player Hit
if (input == "hit") {
playerHand.push(gameDeck.pop());
outputMessage =
displayPlayerAndDealers(playerHand, dealerHand) +
'<br> You drew another card. <br>Please input "hit" or "stand".';
}

// Player Stand
else if (input == "stand") {
// calculate the total hand value of both player and dealer
var playerHandTotalValue = calculateTotalHandValue(playerHand);
var dealerHandTotalValue = calculateTotalHandValue(dealerHand);

while (dealerHandTotalValue < 17) {
dealerHand.push(gameDeck.pop());
dealerHandTotalValue = calculateTotalHandValue(dealerHand);
}

// compare total hand value
// same value -> tie
if (playerHandTotalValue == dealerHandTotalValue) {
outputMessage =
displayPlayerAndDealers(playerHand, dealerHand) +
"It is a tie!" +
displayHandTotalValues(playerHandTotalValue, dealerHandTotalValue);
}
// player higher value -> player wins
else if (playerHandTotalValue > dealerHandTotalValue) {
outputMessage =
displayPlayerAndDealers(playerHand, dealerHand) +
"Player wins!" +
displayHandTotalValues(playerHandTotalValue, dealerHandTotalValue);
}

// dealer higher value -> dealer wins
else {
outputMessage =
displayPlayerAndDealers(playerHand, dealerHand) +
"Dealer wins!" +
displayHandTotalValues(playerHandTotalValue, dealerHandTotalValue);
}
}
// Input validation
else {
outputMessage =
'Wrong input... only "hit" or "stand" are valid. <br><br>' +
displayPlayerAndDealers(playerHand, dealerHand);
}

return outputMessage;
}
};

// calculate the total hand value of both player and dealer
// compare total hand value
// same value -> tie
// player higher value -> player wins
// dealer higher value -> dealer wins
// change game mode
// appropriate output messag