seed = 1   /* seed of the random number generator */
scale = 0

/* Random number from 0 to 32767. */
define rand() {
	/* Formula (from POSIX) for random numbers of low quality. */
	seed = (seed * 1103515245 + 12345) % 4294967296
	return ((seed / 65536) % 32768)
}

/* Shuffle the first _count_ elements of shuffle[]. */
define shuffle(count) {
	auto b, i, j, t

	i = count
	while (i > 0) {
		/* j = random number in [0, i) */
		b = 32768 % i  /* want rand() >= b */
		while (1) {
			j = rand()
			if (j >= b) break
		}
		j = j % i

		/* decrement i, swap shuffle[i] and shuffle[j] */
		t = shuffle[--i]
		shuffle[i] = shuffle[j]
		shuffle[j] = t
	}
}

/* Test program. */
define print_array(count) {
	auto i
	for (i = 0; i < count - 1; i++) print shuffle[i], ", "
	print shuffle[i], "\n"
}

for (i = 0; i < 10; i++) shuffle[i] = 11 * (i + 1)
"Original array: "; trash = print_array(10)

trash = shuffle(10)
"Shuffled array: "; trash = print_array(10)
quit