随机从纸牌中获得一次 select 对象

Question

I pretty sure my remainder operator is in the wrong place, I've tried a few different variations, program still runs but pulls the same card more than once:

Card [] deck = {card0, card1, card2, card3, card4, card5, card6, card7, card8, card9, card10, card11, card12, card13,
        card14, card15, card16, card17, card18, card19, card20, card21, card22, card23, card24, card25, card26, card27, card28,
            card29, card30, card31, card32, card33, card34, card35, card36, card37, card38, card39, card40, card41, card42, card43,
            card44, card45, card46, card47, card48, card49, card50, card51,
        };
for (int i = 0; i<deck.length;i++){
    deck[i] = deck[i%51];
    }
for (int i = 0; i<deck.length; i++){
    index = (int)(Math.random()*deck.length);
    deck[index] = deck[i];

    System.out.println(deck[i] + " ");

    }

I know the deck isn't created in the most efficient manner, that's due to limitations of the assignment. I've only included a small piece of the code, because I think the issue is with my for loop and remainder operator.

Answer 1

The trick is to randomly shuffle the deck and then output it in the shuffled order.

Have a look at Collections.shuffle .

Answer 2

Not sure what are you trying to do here, since i%51 is always equal to i in this case:

for (int i = 0; i<deck.length;i++){
    deck[i] = deck[i%51];
    }

Now to generate a random number between 0 and 50, you need something like

int randomInt = (int)(50.0 * Math.random());

Thus you should use:

for (int i = 0; i<deck.length; i++){
    index = (int)((deck.length-1) * Math.random());
    System.out.println(deck[index] + " ");
    }

But be sure that, some duplicates you may see using this method. If you want each card to be drawn/displayed only once, then use Collections.shufffle(..)

List<Card> deckList = Arrays.asList(deck);
Collections.shuffle(deckList);
for(Card card : deckList){
  System.out.println(card);
}