Blackjack Simulation Library

A C library that can be used to perform probability simulations on the outcome from standing or hitting in Blackjack. The library assumes the knowledge of the remaining cards in the deck.

API

Running simulations

void blackjack_run_simulations(
    blackjack_card_t *deck, int deck_length, // The remaining parts in the deck (this will be shuffled)
    blackjack_card_t *hand, int hand_length, // The players hand, this must have room for one more card
    blackjack_card_t dealer_card, // The dealers card
    blackjack_simulation_results_t *results, // The results of the simulation are written here
    int simulations // The number of simulations to perform
);

Shuffling cards

void blackjack_shuffle_cards(blackjack_card_t *cards, int length);

Code Example

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

#include "../blackjack.h"

const int simulations = 100;

int main(int argc, char *argv[])
{
    blackjack_simulation_results_t results;

    // These are the remaining cards in the deck
    blackjack_card_t deck[] = { 5, 7, BLACKJACK_ACE, 2, BLACKJACK_QUEEN, BLACKJACK_QUEEN, 4, 10 };

    // This is the players hand (it must have space for one more card to allow for simulating taking a new card)
    blackjack_card_t hand[3] = { 6, 7 };

    // This is the card that the dealer has
    blackjack_card_t dealer_card = 9;

    // Seed the random number generator
    srand(time(NULL));

    // Run the simulations
    // This will scramble the deck, write to the next card in the hand array and fill the results structure
    blackjack_run_simulations(deck, sizeof(deck) / sizeof(blackjack_card_t), hand, 2, dealer_card, &results, simulations);

    // Print the results
    printf(
        "Hit Results:\n"
            "\tWin Probability:         %d%%\n"
            "\tLose Probability:        %d%%\n"
            "\tDraw Probablity:         %d%%\n"
            "\tBust Probability:        %d%%\n"
            "\tDealer Bust Probability: %d%%\n"
        "\n"
        "Stand Results:\n"
            "\tWin Probability:         %d%%\n"
            "\tLose Probability:        %d%%\n"
            "\tDraw Probablity:         %d%%\n"
            "\tDealer Bust Probability: %d%%\n"
        "\n",
        results.hit_wins, results.hit_loses, results.hit_draws, results.hit_bust, results.hit_dealer_bust,
        results.stand_wins, results.stand_loses, results.stand_draws, results.stand_dealer_bust
    );

    return 0;
}

Output:

Hit Results:
	Win Probability:         18%
	Lose Probability:        78%
	Draw Probablity:         4%
	Bust Probability:        40%
	Dealer Bust Probability: 12%

Stand Results:
	Win Probability:         21%
	Lose Probability:        79%
	Draw Probablity:         0%
	Dealer Bust Probability: 21%

For further examples, please see the examples directory in the repository.