blackjack.c - learning exercise

blackjack.c

/* A simple blackjack game in C */

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define NUM_SUITS 4
#define NUM_RANKS 13
#define HEARTS 3
#define DIAMONDS 4
#define CLUBS 5
#define SPADE 6
#define H 196
#define V 179
#define TL 218
#define BL 192
#define TR 191
#define BR 217
#define CARD_ROWS 7

struct Card {
   char suit;
   char rank;
   char value;
   bool ace;
};

void play_sound(int n) {
    for(;n > 0; n--) {
        printf("\a");
    }
}

const char rank_code[] = {'2', '3', '4', '5', '6', '7', '8',
                          '9', 'T', 'J', 'Q', 'K', 'A'};
const char suit_code[] = {CLUBS, DIAMONDS, HEARTS, SPADE};

bool better_then(int a, int b) {
    return  a <= 21 && (21 - a) < (21 - b);
}

int get_dealer_action(int dealer_score) {
    // The dealer must stand on 17 or higher and hit below 17.
    if (dealer_score >= 17) {
        return 2;
    }
    return 1;
}

void print_cards(struct Card *cards, size_t num_cards, bool dealer) {
    for (int line = 0; line < CARD_ROWS; ++line) {
        for (unsigned i = 0; i < num_cards; ++i) {
            if (i > 0 && dealer && line > 0 && line < 6) {
                printf("%c#####%c", V, V);
                continue;
            }
            switch (line) {
                case 0:
                    printf("%c%c%c%c%c%c%c", TL, H, H, H, H, H, TR);
                    break;
                case 1:
                    printf("%c%c    %c", V, cards[i].suit, V);
                    break;
                case 3:
                    if (cards[i].rank == 'T') {
                        printf("%c 10  %c", V, V);
                    } else {
                        printf("%c  %c  %c", V, cards[i].rank, V);
                    }
                    break;
                case 5:
                    printf("%c    %c%c", V, cards[i].suit, V);
                    break;
                case 6:
                    printf("%c%c%c%c%c%c%c", BL, H, H, H, H, H, BR);
                    break;
                default:
                    printf("%c     %c", V, V);
                    break;

            }
        }
        printf("\n");
    }
}

void print_game_table(int player_score, int dealer_score, struct Card *player_cards, struct Card *dealer_cards, size_t num_player_cards, size_t num_dealer_cards, bool player_done, bool dealer_done) {
    printf("\nDealer(%2d): \n", dealer_score);
    print_cards(dealer_cards, num_dealer_cards,
                !player_done && !dealer_done);
    printf("\nYou(%2d):\n", player_score);
    print_cards(player_cards, num_player_cards, false);

}

struct Card draw(bool (*in_hand)[NUM_SUITS][NUM_RANKS]) {
    struct Card card;
    int rank, suit;
    for (;;) {
        suit = rand() % NUM_SUITS; /* picks a random suit */
        rank = rand() % NUM_RANKS; /* picks a random rank */
        if (!(*in_hand)[suit][rank]) {
            card.suit = suit_code[suit];
            card.rank = rank_code[rank];
            if (rank == 12) {
                card.value = 1;
                card.ace = 1;
            } else if (rank < 9) {
                card.value = rank + 2;
                card.ace = 0;
            } else {
                card.value = 10;
                card.ace = 0;
            }

            (*in_hand)[suit][rank] = true;
            return card;
        }
    }
}

int get_score(struct Card *cards, size_t num_cards) {
    int sum = 0, aces = 0;
    for (unsigned i = 0; i < num_cards; ++i) {
        sum  += cards[i].value;
        aces += cards[i].ace;
    }
    for (; aces > 0; aces--) {
        if (better_then(sum + 10, sum)) {
            sum += 10;
        }
    }
    return sum;
}

int deal(float *cash, float *bet) {
    bool in_hand[NUM_SUITS][NUM_RANKS] = {{ false }};  // control cards so that they don't repeat
    size_t num_cards = 21;
    struct Card dealer_cards[num_cards], player_cards[num_cards];
    size_t num_dealer_cards = 0, num_player_cards = 0;
    bool player_done = false, dealer_done = false;
    int player_score, dealer_score;

    float result = 0.0f;


    srand((unsigned) time(NULL));

    printf("\n*** Welcome to ClackJack - a C BlackJack! ***\n");

    for (; num_player_cards < 2; ++num_player_cards) {
        player_cards[num_player_cards] = draw(&in_hand);
    }
    for (; num_dealer_cards < 2; ++num_dealer_cards) {
        dealer_cards[num_dealer_cards] = draw(&in_hand);
    }

    int player_action, dealer_action;
    for (;;) {
        player_score = get_score(player_cards, num_player_cards);
        dealer_score = get_score(dealer_cards, num_dealer_cards);

        print_game_table(player_score, dealer_score,
                         player_cards, dealer_cards,
                         num_player_cards, num_dealer_cards,
                         player_done, dealer_done);

        if ((player_score == 21) && (dealer_score == 21)) {
                printf("Tied hand!");
                break;
        }
        else if (player_score == 21) {
            if (num_player_cards == 2) {
                result = (*bet) * 1.5;
                printf("Blackjack!");
                play_sound(4);
            } else {
                result = (*bet);
                printf("You win!");
                play_sound(2);
            }
            break;
        } else if (dealer_score == 21) {
            result = -(*bet);
            printf("Dealer wins!");
            play_sound(1);
            break;
        } else if (player_done && dealer_done) {
            if (better_then(player_score, dealer_score)) {
                result = (*bet);
                printf("You win!");
                play_sound(2);
                break;
            } else {
                result = -(*bet);
                printf("Dealer wins!");
                play_sound(1);
                break;
            }
        }
        else if (player_score > 21) {
            result = -(*bet);
            printf("You busted!");
            play_sound(1);
            break;
        } else if (dealer_score > 21) {
            result = (*bet);
            printf("Dealer busted!");
            play_sound(2);
            break;
        }

        printf("\n(1 - Hit, 2 - Stand)\n");
        printf("What would you like to do? ");

        if (!player_done) {
            scanf("%1d", &player_action);
            switch (player_action) {
                case 1:
                    if (num_player_cards < num_cards) {
                        player_cards[num_player_cards] = draw(&in_hand);
                        ++num_player_cards;
                        player_score = get_score(player_cards, num_player_cards);
                        if (player_score >= 21) {
                            player_done = true;
                        }
                    }
                    break;
                case 2:
                    player_done = true;
                    break;
            }
        }

        // Once the dealer has dealt additional cards to all the players, the dealer draws cards for his/her hand.
        if (player_done && !dealer_done) {
            dealer_action = get_dealer_action(dealer_score);
            switch (dealer_action) {
                case 1:
                    dealer_cards[num_dealer_cards] = draw(&in_hand);
                    ++num_dealer_cards;
                    break;
                case 2:
                    dealer_done = true;
                    break;
            }
            dealer_score = get_score(dealer_cards, num_dealer_cards);
            if (dealer_score >= 21) {
                dealer_done = true;
            }
        }
    }
    if (result > 0) {
        printf(" You've earned $%.2f\n", result);
    } else if (result < 0) {
        printf(" You've lost $%.2f\n", result);
    }
    return result;
}

void change_bet(float *cash, float *bet) {
    float new_bet;
    for (;;) {
        printf("\nEnter a valid bet: ");
        scanf("%f", &new_bet);
        if (new_bet <= (*cash)) {
            (*bet) = new_bet;
            return;
        }
    }
}


int main(void) {
    float cash = 1000.0f, bet = 250.0f;
    float *cash_p = &cash;
    float *bet_p = &bet;
    int player_action;
    do {
        if (cash < bet) {
            bet = cash;
        }
        if (cash <= 0.01f) {
            printf("You are broke! Sounds like a good time to stop...");
            break;
        }
        printf("\n(Options: 1 - Deal (bet %.2f); 2 - Change bet; 0 - Quit)\n",
               bet);
        printf("What would you like to do? (cash %.2f)", cash);
        scanf("%1d", &player_action);
        switch (player_action) {
            case 1:
                cash += deal(cash_p, bet_p);
                break;
            case 2:
                change_bet(cash_p, bet_p);
                break;
            default:
                return 0;
                break;
        }
    } while (1);

    printf("\n");

    return 0;
}

Screenshot: