Programming Forums > Application Development > Java

TCStyle · Mar 22nd, 2007, 11:51 AM

I'm writing a black jack game and I want it so that whenever a card is picked it is eliminated from the deck. I wrote a method to do such a thing, but it doesn't work. Any help?

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import javax.swing.JOptionPane;
public class main {
    public static String cardName(int num) {
        String cName[] = {"Two of hearts", "Two of spades", "Two of diamonds", "Two of clubs",
                          "Three of hearts", "Three of spades", "Three of diamonds", "Three of clubs",
                          "Four of hearts", "Four of spades", "Four of diamonds", "Four of clubs",
                          "Five of hearts", "Five of spades", "Five of diamonds", "Five of clubs",
                          "Six of hearts", "Six of spades", "Six of diamonds", "Six of clubs",
                          "Seven of hearts", "Seven of spades", "Seven of diamonds", "Seven of clubs",
                          "Eight of hearts", "Eight of spades", "Eight of diamonds", "Eight of clubs",
                          "Nine of hearts", "Nine of spades", "Nine of diamonds", "Nine of clubs",
                          "Ten of hearts", "Ten of spades", "Ten of diamonds", "Ten of clubs",
                          "King of hearts", "King of spades", "King of diamonds", "King of clubs",
                          "Queen of hearts", "Queen of spades", "Queen of diamonds", "Queen of clubs",
                          "Jack of hearts", "Jack of spades", "Jack of diamonds", "Jack of clubs"};
        return cName[num];
    }
    public static int randCard() {
        int rand = (int)(Math.random()*53), temp = 0;
        int cDeck[] = {2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11};
        boolean lCond = true;
        while (lCond == true) {
            if (cDeck[rand] != 0) {
                temp = cDeck[rand];
                cDeck[rand] = 0;
                lCond = false;  
            } else {
                rand = (int)(Math.random()*53);
                lCond = true;
            }
        }
        return rand;
    }
    public static void main(String args[]) {
        System.out.println();
        for (int x = 1; x < 30; x++) {
            System.out.println(cardName(randCard()));
        }
    }
}

import javax.swing.JOptionPane;
public class main {
    public static String cardName(int num) {
        String cName[] = {"Two of hearts", "Two of spades", "Two of diamonds", "Two of clubs",
                          "Three of hearts", "Three of spades", "Three of diamonds", "Three of clubs",
                          "Four of hearts", "Four of spades", "Four of diamonds", "Four of clubs",
                          "Five of hearts", "Five of spades", "Five of diamonds", "Five of clubs",
                          "Six of hearts", "Six of spades", "Six of diamonds", "Six of clubs",
                          "Seven of hearts", "Seven of spades", "Seven of diamonds", "Seven of clubs",
                          "Eight of hearts", "Eight of spades", "Eight of diamonds", "Eight of clubs",
                          "Nine of hearts", "Nine of spades", "Nine of diamonds", "Nine of clubs",
                          "Ten of hearts", "Ten of spades", "Ten of diamonds", "Ten of clubs",
                          "King of hearts", "King of spades", "King of diamonds", "King of clubs",
                          "Queen of hearts", "Queen of spades", "Queen of diamonds", "Queen of clubs",
                          "Jack of hearts", "Jack of spades", "Jack of diamonds", "Jack of clubs"};
        return cName[num];
    }
    public static int randCard() {
        int rand = (int)(Math.random()*53), temp = 0;
        int cDeck[] = {2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11};
        boolean lCond = true;
        while (lCond == true) {
            if (cDeck[rand] != 0) {
                temp = cDeck[rand];
                cDeck[rand] = 0;
                lCond = false;  
            } else {
                rand = (int)(Math.random()*53);
                lCond = true;
            }
        }
        return rand;
    }
    public static void main(String args[]) {
        System.out.println();
        for (int x = 1; x < 30; x++) {
            System.out.println(cardName(randCard()));
        }
    }
}

The Dark · Mar 22nd, 2007, 8:20 PM

The cDeck variable is recreated every time you call randCard(). You could make it static, so that it keeps its value from one call to the next, but that does mean that you would only be able to run through the deck once in your program. You might have to change the code so you can initialise a deck and pass it in to randCard instead.

Also, your random calculation gives a number from 0 to 52, but your cDeck array only goes from 0 to 51 and your cName array only goes from 0 to 47.

Similarly your cardname array is recreated every time you call cardName(0, which is not very efficient.

DaWei · Mar 22nd, 2007, 9:02 PM

In other words, you might want to consider playing with a full deck. You also might want to consider the various ways of reusing certain values, instead of replicating them over and over. Inefficiencies are easily concealed by the availability of copious resources, but what if you had a deck with twelve jillion cards?

titaniumdecoy · Mar 22nd, 2007, 10:00 PM

You could use an ArrayList (make sure it is a member variable of the class) to store objects representing cards (perhaps Integer objects). You could then use the remove(int index) method with a random index to both remove and return a random object.

mrynit · Mar 23rd, 2007, 7:42 AM

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Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4
        at Game.cardName(Game.java:16)
        at Game.main(Game.java:37)

first letter of class name has to be Capialized.

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  while (lCond == true)

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  while (lCond)

lCond is a boolean you dont need to test if its value is equivolant to true time by means of ==. by its self in a condition statment its value is tested.

pegasus001 · Mar 23rd, 2007, 12:46 PM

What have classes done to you?

Quote:

Originally Posted by DaWei

In other words, you might want to consider playing with a full deck.

lol.

TCStyle · Mar 23rd, 2007, 1:01 PM

How do I declare my array as static so that it doesn't recreate itself?

titaniumdecoy · Mar 23rd, 2007, 1:03 PM

Declare it outside the method.

TCStyle · Mar 23rd, 2007, 2:24 PM

Alright so I initialized and assigned my array in my main method and I pass it into my randCard() method every time I call it. Now, how can I manipulate my array from inside my randCard() method?

titaniumdecoy · Mar 23rd, 2007, 6:21 PM

You can alter the values stored in an array, but you cannot alter the number of elements in the array once it has been created. If you need to do this, use an ArrayList.

Mar 22nd, 2007, 11:51 AM	#1
TCStyle Programmer Join Date: Jan 2005 Location: Albany, NY Posts: 43 Rep Power: 0	Textbased blackjack. I'm writing a black jack game and I want it so that whenever a card is picked it is eliminated from the deck. I wrote a method to do such a thing, but it doesn't work. Any help? (Toggle Plain Text) import javax.swing.JOptionPane; public class main { public static String cardName(int num) { String cName[] = {"Two of hearts", "Two of spades", "Two of diamonds", "Two of clubs", "Three of hearts", "Three of spades", "Three of diamonds", "Three of clubs", "Four of hearts", "Four of spades", "Four of diamonds", "Four of clubs", "Five of hearts", "Five of spades", "Five of diamonds", "Five of clubs", "Six of hearts", "Six of spades", "Six of diamonds", "Six of clubs", "Seven of hearts", "Seven of spades", "Seven of diamonds", "Seven of clubs", "Eight of hearts", "Eight of spades", "Eight of diamonds", "Eight of clubs", "Nine of hearts", "Nine of spades", "Nine of diamonds", "Nine of clubs", "Ten of hearts", "Ten of spades", "Ten of diamonds", "Ten of clubs", "King of hearts", "King of spades", "King of diamonds", "King of clubs", "Queen of hearts", "Queen of spades", "Queen of diamonds", "Queen of clubs", "Jack of hearts", "Jack of spades", "Jack of diamonds", "Jack of clubs"}; return cName[num]; } public static int randCard() { int rand = (int)(Math.random()53), temp = 0; int cDeck[] = {2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11}; boolean lCond = true; while (lCond == true) { if (cDeck[rand] != 0) { temp = cDeck[rand]; cDeck[rand] = 0; lCond = false; } else { rand = (int)(Math.random()53); lCond = true; } } return rand; } public static void main(String args[]) { System.out.println(); for (int x = 1; x < 30; x++) { System.out.println(cardName(randCard())); } } } import javax.swing.JOptionPane; public class main { public static String cardName(int num) { String cName[] = {"Two of hearts", "Two of spades", "Two of diamonds", "Two of clubs", "Three of hearts", "Three of spades", "Three of diamonds", "Three of clubs", "Four of hearts", "Four of spades", "Four of diamonds", "Four of clubs", "Five of hearts", "Five of spades", "Five of diamonds", "Five of clubs", "Six of hearts", "Six of spades", "Six of diamonds", "Six of clubs", "Seven of hearts", "Seven of spades", "Seven of diamonds", "Seven of clubs", "Eight of hearts", "Eight of spades", "Eight of diamonds", "Eight of clubs", "Nine of hearts", "Nine of spades", "Nine of diamonds", "Nine of clubs", "Ten of hearts", "Ten of spades", "Ten of diamonds", "Ten of clubs", "King of hearts", "King of spades", "King of diamonds", "King of clubs", "Queen of hearts", "Queen of spades", "Queen of diamonds", "Queen of clubs", "Jack of hearts", "Jack of spades", "Jack of diamonds", "Jack of clubs"}; return cName[num]; } public static int randCard() { int rand = (int)(Math.random()53), temp = 0; int cDeck[] = {2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11}; boolean lCond = true; while (lCond == true) { if (cDeck[rand] != 0) { temp = cDeck[rand]; cDeck[rand] = 0; lCond = false; } else { rand = (int)(Math.random()53); lCond = true; } } return rand; } public static void main(String args[]) { System.out.println(); for (int x = 1; x < 30; x++) { System.out.println(cardName(randCard())); } } } __________________ meh...

Mar 22nd, 2007, 9:02 PM	#3
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	In other words, you might want to consider playing with a full deck. You also might want to consider the various ways of reusing certain values, instead of replicating them over and over. Inefficiencies are easily concealed by the availability of copious resources, but what if you had a deck with twelve jillion cards? __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Mar 23rd, 2007, 7:42 AM	#5
mrynit Hobbyist Programmer Join Date: Mar 2006 Location: WA, USA Posts: 343 Rep Power: 3	(Toggle Plain Text) Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4 at Game.cardName(Game.java:16) at Game.main(Game.java:37) Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4 at Game.cardName(Game.java:16) at Game.main(Game.java:37) first letter of class name has to be Capialized. (Toggle Plain Text) while (lCond == true) while (lCond == true) (Toggle Plain Text) while (lCond) while (lCond) lCond is a boolean you dont need to test if its value is equivolant to true time by means of ==. by its self in a condition statment its value is tested. __________________ i dont know much about programming but i try to help

Mar 23rd, 2007, 1:01 PM	#7
TCStyle Programmer Join Date: Jan 2005 Location: Albany, NY Posts: 43 Rep Power: 0	How do I declare my array as static so that it doesn't recreate itself? __________________ meh...

Mar 23rd, 2007, 2:24 PM	#9
TCStyle Programmer Join Date: Jan 2005 Location: Albany, NY Posts: 43 Rep Power: 0	Alright so I initialized and assigned my array in my main method and I pass it into my randCard() method every time I call it. Now, how can I manipulate my array from inside my randCard() method? __________________ meh...

Mar 22nd, 2007, 8:20 PM	#2
The Dark Expert Programmer Join Date: Jun 2005 Posts: 894 Rep Power: 4	The cDeck variable is recreated every time you call randCard(). You could make it static, so that it keeps its value from one call to the next, but that does mean that you would only be able to run through the deck once in your program. You might have to change the code so you can initialise a deck and pass it in to randCard instead. Also, your random calculation gives a number from 0 to 52, but your cDeck array only goes from 0 to 51 and your cName array only goes from 0 to 47. Similarly your cardname array is recreated every time you call cardName(0, which is not very efficient.

Mar 22nd, 2007, 10:00 PM	#4
titaniumdecoy Expert Programmer Join Date: Nov 2005 Posts: 932 Rep Power: 4	You could use an ArrayList (make sure it is a member variable of the class) to store objects representing cards (perhaps Integer objects). You could then use the remove(int index) method with a random index to both remove and return a random object.

Mar 23rd, 2007, 1:03 PM	#8
titaniumdecoy Expert Programmer Join Date: Nov 2005 Posts: 932 Rep Power: 4	Declare it outside the method.

Mar 23rd, 2007, 6:21 PM	#10
titaniumdecoy Expert Programmer Join Date: Nov 2005 Posts: 932 Rep Power: 4	You can alter the values stored in an array, but you cannot alter the number of elements in the array once it has been created. If you need to do this, use an ArrayList.

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Programming Forums > Application Development > Java

Textbased blackjack.