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# How do I write a method to win in blackjack?

Posted on 2011-09-13
Medium Priority
559 Views
Here are my Card, DeckOfCards, and TwoPlayerBlackJack classes:

TwoPlayerBlackJack class:

import java.util.ArrayList;
/**
* Write a description of class TwoPlayerBlackJack here.
*
* @version (a version number or a date)
*/
public class TwoPlayerBlackJack
{

private String rank;
private ArrayList<Card> blackJack;
private char suit;

/**
* Constructor for objects of class TwoPlayerBlackJack
*/
public TwoPlayerBlackJack()
{
String[] ranks = Card.getPossibleRanks();
char[] suites = Card.getPossibleSuits();
blackJack = new ArrayList<Card>();
for (int i = 0; i < Card.getPossibleRanks().length ; i++)
{
for (int j = 0; j < Card.getPossibleSuits().length; j++)
{
}
}
}

/**
* The method takes an object of class Card and return an integer that represents the value of that card.
* The values of the cards are determines as follows:
* two is 2, three is 3, ...., nine is 9, ten is 10,  jacks, queens and kings are all 10.
* Ace could be either 1 or 11 but for this method we will assume that the value Ace is always 1
*/
public int getCardValue(Card c){
String rank = c.getRank();

int value = -1;
try {
value = new Integer(rank);
}catch(Exception ex){
if(rank.equals("Ace"))value = 1;
else{ value = 10;

}

}
return value;
}

/**
* Given a hand cards (i.e. ArrayList of Cards) return an integer value that corresponds to the hand value
* (i.e. sum of all card values).
*/
public int computeHandValue(ArrayList <Card> hand)
{

int sum = 0;
int numAces = 0;

for(Card c: hand){
int value = getCardValue(c);
sum += value;
if(c.getRank().equals("Ace"))
numAces++;

}
if(sum<12 && numAces >0)sum += 10;

return sum;

}

/**
* Method display hand value display the value of each card followed by the hand value
*/
public void printHandValue(ArrayList <Card> hand)
{
System.out.println(computeHandValue(hand));
}

/**
* Method that takes two Array Lists of Cards (i.e. two card hands) and determines the winner
* of the BlackJack game.
* 1 – the first hand won the game
* 0 – nobody won, it is a push
* -1 – the first hand lost the game
*/
public int isWinner(ArrayList <Card> hand01, ArrayList <Card> hand02)
{

if(computeHandValue(hand01)==computeHandValue(hand02)){
return 0;

if(computeHandValue(hand01)>computeHandValue(hand02)&&(computeHandValue(hand01)<=21))
return 1;

if(computeHandValue(hand01)<computeHandValue(hand02)&&(computeHandValue(hand02)<=21))
return 1;

if((computeHandValue(hand01)&&computeHandValue(hand02))>21)
return 0;

if((computeHandValue(hand01) <= 21) && (computeHandValue(hand02) >= 21))
return -1;

if((computeHandValue(hand02) <= 21) && (computeHandValue(hand01) >= 21))
return -1;
}
}

DeckOfCards:

import java.util.Random;
import java.util.ArrayList;
public class DeckOfCards
{
private ArrayList<Card> deck;
Random getRandom = new Random();

/**
* Default constructor creates an Array List of Cards and populates it with 52 different cards
*/
public DeckOfCards()
{
deck = new ArrayList<Card>();
resetDeckOfCards();
}

/**
* Remove all leftover cards from the ArrayList of Cards called deck
* Populate an empty deck with 52 new cards...
*/
public void resetDeckOfCards()
{
String[] ranks = Card.getPossibleRanks();
char[] suites = Card.getPossibleSuits();

for (int i = 0; i < Card.getPossibleRanks().length ; i++)
{
for (int j = 0; j < Card.getPossibleSuits().length; j++)
{
}
}
}

/**
* Remove random card of arraylist of cards and return value from method
*/
public Card getCard()
{
if (deck.isEmpty())
resetDeckOfCards();
return deck.remove(getRandom.nextInt(deck.size()));
}

/**
* Return an ArrayList of specified size (i.e. returned cards are being removed from the deck).
*/
public ArrayList<Card> getHand(int size)
{
ArrayList<Card> hand = new ArrayList<Card>();
for (int i = 0; i < size; i++)
{
}
return hand;

}

}

Card class:

public class Card
{

private String rank;//card rank: a number between 2 and 10, or Jack, Queen, King or Ace
private char suit;//card suit: S,C,H,or D
private static String[] Ranks={"2","3","4","5","6","7","8","9","10","Jack","Queen","King","Ace"};
private static char[] Suites={'C','H','D','S'};

/**
* Default constructor: sets card rank to 2 and card suit to H
*/
public Card()
{
rank="2";
suit='H';

}

/**
* Class constructor: sets card rank and suit to provided values.
*/
public Card(String rank, char suit)
{
this.rank=rank;
this.suit=suit;
}

/**
* Gets the rank
*/
public String getRank()
{
return rank;
}

/**
* Gets the suit
*/
public char getSuit()
{
return suit;
}

/**
* Sets the rank
*/
public void setRank(String rank)
{
this.rank=rank;
}

/**
* Sets the suit
*/
public void setSuit(char suit)
{
this.suit=suit;
}
/**
* Returns an array of possible card ranks
*/
public static String[] getPossibleRanks()
{
return Ranks;
}
/**
* Returns an array of possible card suits
*/

public static char[] getPossibleSuits()
{
return Suites;
}

/**
* Returns string representation of the card that looks as follows:
* 2 of Hearts, 3 of Spades, Jack of Diamonds, etc.
*/
public String toString()
{String suitName = "";
switch (suit){
case 'H':
suitName = rank + " of Hearts";
break;
case 'S':
suitName = rank + " of Spades";
break;
case 'D':
suitName = rank + " of Diamonds";
break;
case 'C':
suitName = rank + " of Clubs";

}
return suitName;
}
}
0
Question by:ryanbecker24
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LVL 47

Expert Comment

ID: 36533392
So waht do you want to get in response to this question ?
0

Author Comment

ID: 36533408
How to write a isWinner of my TwoPlayerBlackJack class using the ArrayList parameters and return the winner, loser, and tie (1,-1,0, respectively)
0

LVL 47

Expert Comment

ID: 36533410
But you have such method there?
0

Author Comment

ID: 36533418
I don't think this is right so thats why I want help

/**
* Method that takes two Array Lists of Cards (i.e. two card hands) and determines the winner
* of the BlackJack game.
* 1 – the first hand won the game
* 0 – nobody won, it is a push
* -1 – the first hand lost the game
*/
public int isWinner(ArrayList <Card> hand01, ArrayList <Card> hand02)
{

if(computeHandValue(hand01)==computeHandValue(hand02)){
return 0;

if(computeHandValue(hand01)>computeHandValue(hand02)&&(computeHandValue(hand01)<=21))
return 1;

if(computeHandValue(hand01)<computeHandValue(hand02)&&(computeHandValue(hand02)<=21))
return 1;

if((computeHandValue(hand01)&&computeHandValue(hand02))>21)
return 0;

if((computeHandValue(hand01) <= 21) && (computeHandValue(hand02) >= 21))
return -1;

if((computeHandValue(hand02) <= 21) && (computeHandValue(hand01) >= 21))
return -1;
}
}

0

LVL 23

Expert Comment

ID: 36533426
Why is no one using the code window?
0

LVL 47

Accepted Solution

for_yan earned 2000 total points
ID: 36533429

I don't think your method is right eirther

(it is tricky to treat Ace, - I'm not sure this part is correct, but anyway);
I think this code should be better (maybe not - I'm not specialits in Blacvkjack):
``````public int isWinner(ArrayList <Card> hand01, ArrayList <Card> hand02)
{

if(computeHandValue(hand01) > 21) return -1;

if(computeHandValue(hand02)  > 21) return 1;

if(computeHandValue(hand01) > computeHandValue(hand02)) return 1;
else  if(computeHandValue(hand01) == computeHandValue(hand02)) return 0;
else return -1;
}
``````
0

LVL 47

Expert Comment

ID: 36533435
Actually in real game there can never be the situation when both > 21
in this method it is possible - so it is not defined who will be the winner in this case.
The above method  assumes that hand01 will lose in this case
0

Author Closing Comment

ID: 36533453
Thank you!
0

LVL 47

Expert Comment

ID: 36533455
Actually if hand01 is the player and hand02 is the dealer then I guess, as soon as hand01 becomes > 21
then player loses no matter what the dealer will get - so in this sense the above method is right
0

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