Program Not Returning Results as Expected. Probably Misuse of "bool"?

Question

I'm new to programming and I had to work on a program that would simulate 10,000 games of craps. I got it to calculate points for house and player just fine until I added in the function "diceRoll" where player rolls again and again until it matches the first roll or 7 (house wins). Now it gives decidedly not random results (such as the house winning 0 times out of 10,000). What did I do wrong?

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

bool diceRoll (int a)
{
    srand( (unsigned)time(NULL));
    int n = 0;
    int b = 0;
    while(n < 1) {
        b = rand() % 12;
        if(b == a || b == 6) n++;
    }
    if(b == 6) return false;
    else return true;
}


int main (void)
{
    srand( (unsigned)time(NULL));
    int a, n, house, player, point;
    house = 0;
    player = 0;
    point = 0;

    for(n = 0; n < 10000; n++) {
        a = rand() % 12;
        if(a == 1 || a == 2 || a == 11) {
            house++;
        }
        else if(a == 6 || a == 10) {
            player++;
        }
        else {
            if(diceRoll(a) == true) player++;
            else house++;
        }
    }

    printf("The house has %i points.\n", house);
    printf("The player has %i points.\n", player);
    return 0;
}

Answer 1

You've over-seeded, remove the call to srand() in diceRoll and you should be fine (this ignores bias due to modulo usage).

Answer 2

Only seed in main() (and not in a loop) and don't seed it in the diceRoll(a) function.

I ran it your way and got house = 2, player = 9998.

Removing the srand((unsigned)time(null)); in the diceroll(a) came back with:

The house has 5435 points

The player has 4565 points

I assume that is what you wanted

bool diceRoll (int a)
{
    int n = 0;
    int b = 0;
    while(n < 1) {
        b = rand() % 12;
        if(b == a || b == 6) n++;
    }
    if(b == 6) return false;
    else return true;
}

int main (void)
{
    srand( (unsigned)time(NULL));
    int a, n, house, player, point;
    house = 0;
    player = 0;
    point = 0;

    for(n = 0; n < 10000; n++) {
        a = rand() % 12;
        if(a == 1 || a == 2 || a == 11) {
            house++;
        }
        else if(a == 6 || a == 10) {
            player++;
        }
        else {
            if(diceRoll(a) == true) player++;
            else house++;
        }
    }

    printf("The house has %i points.\n", house);
    printf("The player has %i points.\n", player);
    return 0;
}