Random extraction of 5 cards from a deck

const int CARDS = 52;
int card[CARDS]; // the 'card' array represents all of the cards
int i, deck_cards;
// initialization
for (i=0; i< CARDS; i++)
  card[i]=i;
// 'deck_cards' is the limit of the deck, it separates the 
// cards still inside the deck from the extracted ones
deck_cards = CARDS;

// random extraction of five cards
for (i=0; i<5; i++)
{
  // r is the newly extracted card index
  int r = rand() % deck_cards;

  // the trick is here: we move the choosen card at the current deck
  // limit and decrease the deck size by one.
  // this is accomplished swapping card[r] with card[deck_cards-1]
  int temp = card[r];
  card[r] = card[deck_cards-1];
  card[deck_cards-1] = temp;

  deck_cards--;
}
// now let't print out the random choosen cards
for (i=0; i<5; i++)
{
  printf("extracted card[%d]=%d\n", i, card[deck_cards+i]
}

for (i=0; i<5; i++)
{ 
  // r is the newly extracted card index
  int r = rand() % (CARDS-i);  
  // swap card[r] with card[CARDS-1-i]
  int temp = card[r];
  card[r] = card[CARDS-1-i];
  card[CARDS-1-i] = temp;
}