// Given a sorted set of digits, print all of them in counting order.
// digits[] - the set of digits allowed. They are assumed to be in the set {0-9}, but it will work with larger numbers as well.
// range - the length of the resulting number (i.e., how many digits to print)
// numDigits - the size of the set of digits represented by digits[]
//
// There are probably slicker ways to do this: see http://stackoverflow.com/questions/228796/algorithm-odometer-brute-force
// but this one is fast.


int odometer(int digits[], int range, int numDigits) {
int index[range];
memset(index, 0, sizeof (index));
int result[range];
memset(result, 0, sizeof (result));
int x; //, tempindex;

/* initialize result to the first digit */
for (x = 0; x < range; x++) {
result[x] = digits[index[x]];
}

/* go to the right-most digit in result */
int p = range - 1;

bool done = false;
while (!done) {
for (x = 0; x < range; x++) {
printf("%d ", result[x]);
}
printf("\n");

if (result[p] < digits[numDigits-1]) {
result[p] = digits[++index[p]];
} else {
/* move left until you find a number < greatest digit */
while (p >= 0 && result[p] == digits[numDigits-1]) {
--p;
}
if (p < 0) {
done = true;
} else {
result[p] = digits[++index[p]];
while (p < (range-1)) {
p++;
result[p] = digits[0];
index[p] = 0;
}
}
}
}

return EXIT_SUCCESS;
}



Read more: http://feeds.dzone.com/~r/dzone/snippets/~3/ciKtdbaNV3U/13187