bsearch2.c

int binarysearch(DataType t)
    /* return (any) position
       if t in sorted x[0..n-1] or
       -1 if t is not present */
{
    int l, u, m;
    l = 0;
    u = n-1;
    while (l <= u) {
        m = (l + u) / 2;
        if (x[m] < t)
            l = m+1;
        else if (x[m] == t)
            return m;
        else /* x[m] > t */
            u = m-1;
    }
    return -1;
}