peters.c

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

#define NUM_TRIALS 1e9

int randint(int n);
unsigned int play(void);

int main(void) {
    srand(time(NULL));

    unsigned long long int total = 0;
    for (int i = 0; i < NUM_TRIALS; i++) {
        total += play();
    }

    printf("average win: %0.2f\n", total/NUM_TRIALS);

    return 0;
}

unsigned int play(void) {
    unsigned int pot = 1;

    while (rand() % 2 == 0)
        pot *= 2;

    return pot;
}