link printf, factors

$define MAX_N 20
$define TIMES 1000000
$define RAND_MAX 2147483647

procedure expected(n)
    local sum := 0
    every i := 1 to n do
        sum +:= factorial(n) / (n ^ i) / factorial(n - i)
    return sum
end

procedure test(n, times)
    local i, count := 0, x, bits
    every i := 0 to times-1 do {
	x := 1
	bits := 0
	while iand(bits, x)=0 do {
            count +:= 1
            bits := ior(bits, x)
            x := ishift(1 , ?n-1)
        }
    }
    return count
end

procedure main(void)
    local n, cnt, avg, theory, diff
    write(" n\tavg\texp.\tdiff\n", repl("-",29))
    every n := 1 to MAX_N do {
        cnt := test(n, TIMES)
        avg := real(cnt) / TIMES
        theory := expected(n)
        diff := (avg / theory - 1) * 100
        printf("%2d %8.4r %8.4r %6.3r%%\n", n, avg, theory, diff)
    }
    return 0
end