bsearch

int* bsearch(int val, int* base, int nelems)
{
    if (base == NULL || nelems == 0)
        return NULL;

    int lo = 0;
    int hi = nelems - 1;

    for (;;)
    {
        int m = (lo + hi + 1) / 2;

        if (base[m] == val)
            return base + m;
        else if (lo == hi)
            return NULL;
        else if (base[m] < val)
            lo = m;
        else if (base[m] > val)
            hi = m;
    }
}