Weighted random

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

static int weighted_random()
{
    int weights[] = { 50, 50 };
    int count = sizeof(weights) / sizeof(int);

    int sum = 0;

    for (int i = 0; i < count; ++i)
    {
        sum += weights[i];
    }

    int rnd = rand() % sum;

    int c = 0;

    for (int i = 0; i <= count; ++i)
    {
        if (rnd < c)
        {
            return i - 1;
        }

        c += weights[i];
    }

    return -1;
}

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

    int randoms[2] = { 0, 0 };

    for (int i = 0; i < 10000000; ++i)
    {
        randoms[weighted_random()]++;
    }

    printf("weighted_random 0: %d\n", randoms[0]);
    printf("weighted_random 1: %d\n", randoms[1]);

    return 0;
}