If all you want is a shuffle type of operation on a list, then it is fairly straight-forward:
void Shuffle (int num_in_list, int *list) { // Deck-of-cards type shuffle
int item, swap, loop;
for (loop = num_in_list; loop > 1; loop--) { // Move down the list
swap = loop * rand () / (RAND_MAX + 1); // Choose a random item from the original list
item = list [swap]; // Remember it
list [swap] = list [loop - 1]; // Exchange it with the top one of the new list
list [loop - 1] = item;
}
}
But I'm not sure what you mean by your requirement of "without having numbers twice". The above function will not repeat a list entry, if that's all you want.
JR
