14. CardGame

This program "deals" a poker hand, and checks for pairs, three of kind, and four a kind.

Description: This program "deals" a poker hand, and checks for pairs, three of kind, and four a kind. Just the beginning of what could be a fund poker-playing game.

Code

package asu.cardgame;

import java.util.Scanner;

public class CardGame {
    
    public static int[] hand = new int[5];
    public static int[] deck = new int[52];
    
    public static void main(String[] args) {
        //lab4_execise_1();
        lab4_exercise_4();
    }
    
    private static int randomInteger(int a, int b) {
        return (int) ((b - a) * Math.random() + a);
    }
    
    private static void lab4_execise_1() {
        //generate two integers
        //for timing:
        long start, stop;
        start = System.currentTimeMillis();
        System.out.println("start time =" + start);
        int n1, n2;
        int n_digits = 2;
        int a = (int) Math.pow(10, n_digits - 1);
        int b = (int) Math.pow(10, n_digits);
        n1 = randomInteger(a, b);
        n2 = randomInteger(a, b);
        System.out.println(" " + n1);
        System.out.println(" " + n2);
        System.out.println("+___");
        int correct = n1 + n2;
        Scanner input = new Scanner(System.in);
        int answer = input.nextInt();
        while (answer != correct) {
            System.out.println("Wrong, try again:");
            answer = input.nextInt();
        }
        System.out.println("Got it");
        stop = System.currentTimeMillis();
        System.out.println("It took you " + (stop - start) / 1000.0 + " seconds.");
    }
    
    private static void lab4_exercise_4() {
        // choose a random card
        // model the deck as 52 cards, indexed from 0 to 51.
        // print the whole deck:
        //printDeck();
        initializeDeck();
        shuffleDeck();
        dealPokerHand();
        sortHand();
        displayPokerHand();
        if (hasPair() >= 0) {
            System.out.println("Has a pair of " + getRank(hasPair() % 13) + "'s");
        }
        
        if(hasThree() >= 0) {
            System.out.println("Has three " + getRank(hasThree() % 13) + "'s");
        }
    }
    
    private static int getSuit(int suit) {
        
        switch (suit) {
            case 0:
                return 9829; //hearts
            case 1:
                return 9830; //diamonds
            case 2: 
                return 9824; //spades
            case 3:
                return 9827; //clubs
            default:
                return 9837; //flat
        }
    }
    
    private static char getRank(int rank) {
        if (rank > 0 && rank < 9) {
            return (char) (49 + rank);
        }
        switch (rank) {
            case 0:
                return 'A';
            case 9:
                return 'T';
            case 10:
                return 'J';
            case 11:
                return 'Q';
            case 12:
                return 'K';
        }
        return (char) rank;   
    }
    
    private static void printDeck() {
        for (int i = 0; i < 52; i++) {
            int rank = i % 13;
            int suit = i / 13;
            System.out.println(getRank(rank) + " " + (char) getSuit(suit));
        }
    }
    
    private static void initializeDeck() {
        for (int i = 0; i < 52; i++) {
            deck[i] = i;
        }
    }
    
    private static void shuffleDeck() {
        
        for(int i = 0; i < 10000; i++) {
            int card1 = randomInteger(0, 52);
            int card2 = randomInteger(0, 52);
            //swap card1 with card2
            int temp = deck[card1];
            deck[card1] = deck[card2];
            deck[card2] = temp;
        }
    }
    
    private static void dealPokerHand() {
        for(int i = 0; i < 5; i++) {
            //hand[i] = randomInteger(0, 52);
            hand[i] = deck[i];
        }
    }
    
    private static void displayPokerHand(){
        
        for (int i = 0; i < 5; i++) {
            char cardRank = getRank(hand[i] % 13);
            char cardSuit = (char) getSuit(hand[i] / 13);
            System.out.print(cardRank + "" + cardSuit);
            System.out.print(" ");
        }
        System.out.println("");
    }
    
    private static int hasPair() {
        for (int i = 0; i < 4; i++) {
            for (int j = i + 1; j > i && j < 5; j++) {
                if (hand[i] % 13 == hand[j] % 13) {
                    return hand[i];
                }
            }
        }
        return -1;
    }
    
    private static int hasThree() {
        //assumes the hand is sorted by rank
        int[] rank = new int[5];
        for (int i = 0; i < 5; i++) {
            rank[i] = hand[i] % 13;
        }
        for (int i = 0; i < 3; i++) {
            if (rank[i] == rank[i+1] && rank[i] == rank[i+2]) {
                return hand[i];
            }
        }
        return -1;
    }
    
    private static void sortHand() {
        int[] rank = new int[5];
        for (int i = 0; i < 5; i++) {
            rank[i] = hand[i] % 13;
        }
        boolean flag = true;
        for (int i = 0; i < 4; i++) {
            if (rank[i] > rank[i + 1]) {
                int temp = rank[i];
                rank[i] = rank[i + 1];
                int temp2 = hand[i];
                hand[i] = hand[i + 1];
                hand[i + 1] = temp2;
                flag = true;
            }
        }
    }
}       

Output

4♣ 4♦ 9♥ 9♠ T♥
Has a pair of 4's