Coin Flip - Single Loop

void coinFlip()
{
    static unsigned int calls = 0, total = 0;       //calls: number of times function has been called; total: accumulative total of flips
    unsigned int sum = 0, flips = 0;    //sum: sum of H/T(H = 0, T = 1)

    do {    //flip the coin 9 times...
        sum += (rand() % 2);    //H = 0, T = 1
        flips++;
    } while (flips < 9);

    total += flips;

    if (sum == 0)       //sum of 9 heads is 0, since H = 0
    {
        cout << "Total flips: " << total
        << "\nNumber of trials to needed get 9 heads: " << calls << endl;
    }
    else
    {
        calls++;
        coinFlip();     //call the function again...
    }
}

int main()
{
    srand(time(NULL));      //seed rand(), so we get a "random" number from it...

    //multithread();
    coinFlip();

    cout << "Press enter to exit...";
    getchar();
}