10_3_3_poker.c

/* Classifies a poker hand */

#include <stdio.h>
#include <stdbool.h>    /* C99 only */
#include <stdlib.h>

#define NUM_RANKS 13
#define NUM_SUITS 4
#define NUM_CARDS 5

/* external variables */
int num_in_rank[NUM_RANKS];
int num_in_suit[NUM_SUITS];
bool straight, flush, four, three;
int pairs;    /* can be 0, 1, or 2 */

/* prototypes */
void read_cards(void);
void analyze_hand(void);
void print_result(void);

/****************************************************************************
 * main: Calls read_cards, analyze_hand, and print_result repeatedly.       *
 ****************************************************************************/
int main(void)
{
    int j, play_times;

    printf("Enter times you want to play: ");
    scanf("%d", &play_times);

    for (j = 1; j <= play_times; j++)
    {
        read_cards();
        analyze_hand();
        print_result();
    }
}

/****************************************************************************
 * read_cards: Reads the cards into the external variables num_in_rank and  *
 *             num_in_suit; check for bad cards and duplicated cards.       *
 ****************************************************************************/
void read_cards(void)
{
    bool card_exists[NUM_RANKS][NUM_SUITS];
    char ch, rank_ch, suit_ch;
    int rank, suit;
    bool bad_card;
    int cards_read = 0;

    for (rank = 0; rank < NUM_RANKS; rank++)
    {
        num_in_rank[rank] = 0;
        for (suit = 0; suit < NUM_SUITS; suit++)
        {
            card_exists[rank][suit] = false;
        }
        
    }

    for (suit = 0; suit < NUM_SUITS; suit++)
    {
        num_in_suit[suit] = 0;
    }
    
    while (cards_read < NUM_CARDS)
    {
        bad_card = false;

        printf("Enter a card: ");

        rank_ch = getchar();
        switch (rank_ch)
        {
            case '0':        exit(EXIT_SUCCESS);
            case '2':           rank = 0; break;
            case '3':           rank = 1; break;
            case '4':           rank = 2; break;
            case '5':           rank = 3; break;
            case '6':           rank = 4; break;
            case '7':           rank = 5; break;
            case '8':           rank = 6; break;
            case '9':           rank = 7; break;
            case 't': case 'T': rank = 8; break;
            case 'j': case 'J': rank = 9; break;
            case 'q': case 'Q': rank = 10; break;
            case 'k': case 'K': rank = 11; break;
            case 'a': case 'A': rank = 12; break;
            default:            bad_card = true;
        }

        suit_ch = getchar();
        switch (suit_ch)
        {
            case 'c': case 'C': suit = 0; break;
            case 'd': case 'D': suit = 1; break;
            case 'h': case 'H': suit = 2; break;
            case 's': case 'S': suit = 3; break;
            default:            bad_card = true;
        }

        while ((ch = getchar()) != '\n')
        {
            if (ch != ' ' ) bad_card = true;
        }
        
        if (bad_card)
            printf("Bad card; ignored. \n");
        else if (card_exists[rank][suit])
            printf("Duplicate card; ignored. \n");
        else
        {
            num_in_rank[rank]++;
            num_in_suit[suit]++;
            card_exists[rank][suit] = true;
            cards_read++;
        }
    }
    
}

/****************************************************************************
 * analyze_hand: Determines whether the hand contains a straight, a flush,  *
 *               four-of-a-kind, and/or three-of-a-kind; determines the     *
 *               number of pairs; stores the results into the external      *
 *               variable straight, flush, four, three, and paires.         *
 ****************************************************************************/
void analyze_hand(void)
{
    int num_consec = 0;
    int rank, suit;

    straight = false;
    flush = false;
    four = false;
    three = false;
    pairs = 0;

    /* check for flush */
    for (suit = 0; suit < NUM_SUITS; suit++)
    {
        if (num_in_suit[suit] == NUM_CARDS)
            flush = true;
    }

    /* check for straight */
    rank = 0;
    while (num_in_rank[rank] == 0) rank++;
    for (; rank < NUM_RANKS && num_in_rank[rank] > 0; rank++)
        num_consec++;
    if (num_consec == NUM_CARDS)
    {
        straight = true;
        return;
    }
    
    /* check for 4-of-a-kind, 3-of-a-kind, and pairs */
    for (rank = 0; rank < NUM_RANKS; rank++)
    {
        if (num_in_rank[rank] == 4) four = true;
        if (num_in_rank[rank] == 3) three = true;
        if (num_in_rank[rank] == 2) pairs++;
    }
}

/****************************************************************************
 * print_result: Prints the classification of the hand, based on the values *
 *               of the external variables straight, flush, four, three,    *
 *               and pairs.                                                 *
 ****************************************************************************/
void print_result(void)
{
    if (straight && flush)        printf("Straight flush");
    else if (four)                printf("Four of a kind");
    else if (three && pairs == 1) printf("Full house"); 
    else if (flush)               printf("Flush");
    else if (straight)            printf("Straight");
    else if (three)               printf("Three of a kind");
    else if (pairs == 2)          printf("Two pairs");
    else if (pairs == 1)          printf("Pair");
    else                          printf("High card");

    printf("\n\n");
}