sem8.c

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

#define NR_OF_PLAYS (1000000)
#define BET (100)
#define PAYOFF (200)

#define MINIMUM_CERTAINTY (0.75)

#define RED (1)
#define BLACK (2)
#define JOKER (0)
#define CONTINUE (-1)

int random_suit(int reds, int blacks, int jokers)
{
    int rand_val = rand() % (reds + blacks + jokers);

    if(rand_val < reds)
    {
        return RED;
    }
    else if(rand_val < (reds + blacks))
    {
        return BLACK;
    }
    else
    {
        return JOKER;
    }
}

int main(int argc, char ** argv)
{
    srand(time(NULL));

    long long cash = 0;

    int playno;
    for(playno = 0; playno < NR_OF_PLAYS; ++playno)
    {
        int reds = 26;
        int blacks = 26;
        int jokers = 1;

        cash -= BET;

        while(reds + blacks + jokers > 0)
        {
            fprintf(stderr, "reds=%2d, blacks=%2d, jokers=%d", reds, blacks, jokers);

            int choise = CONTINUE;
            double p_red = 1.0 * reds / (reds + blacks + jokers);
            fprintf(stderr, ", P(red)=%.3f", p_red);
            if(p_red > MINIMUM_CERTAINTY || (reds + blacks + jokers) == 1)
            {
                choise = RED;
            }

            int card = random_suit(reds, blacks, jokers);
            fprintf(stderr, ", card=%d, choise=%2d\n", card, choise);
            if(choise == RED && card == RED)
            {
                cash += PAYOFF;
                break;
            }

            if(card == RED) --reds;
            if(card == BLACK) --blacks;
            if(card == JOKER) --jokers;
        }

        fprintf(stderr, "%39s cash=%lld\n", " ", cash);
    }

    printf("End balance: %lld\n", cash);

    return 0;
}