8.1 Design the data structures for a generic deck of cards. Explain how you would subclass the data structures to implement blackjack.

这道题让我们设计一个21点纸牌游戏的数据结构，用面向对象的思想来设计。那么既然21点是一种特定的纸牌游戏，它可以是从普通纸牌的基础上派生出来的。所以我们先实现最基本的纸牌类Card，里面包括值和花色，还有一些基本的判断或标记可用性的函数。然后就是基本的牌堆类Deck，可以用来加入牌，洗牌，发牌以及算剩余牌数。还需要一个当前手牌类Hand，可以计算当前分数，可以加牌等。然后就是它们的派生类21点纸牌类BlackJackCard，包括计算值，计算最大最小值，判断是不是Ace等等，然后就是21点手牌类BlackjackHand，计算当前得分，判断是否爆了，是否是21点等等。以下代码为书上代码，有些函数体写实现，所以暂时无法用具体运行。

//C++ defination

enumSuit {Club, Diamond, Heart, Spade};

template

classDeck {public:void setDeckOfCards(vector deckOfCards) {}; //...

void shuffle() {}; //...

intremainingCards() {return _cards.size() -_dealtIndex;

}

vector dealHead(int number) {}; //...

T dealCard() {}; //...

private:

vector_cards;int _dealtIndex = 0;

};classCard {public:

Card(intc, Suit s): _faceValue(c), _suit(s) {};virtual int value() = 0;

Suit suit() {return_suit; };bool isAvailable() { return_available; };void markUnavailable() { _available = false; };void markAvailable() { _available = true; };protected:int_faceValue;

Suit _suit;private:bool _available = true;

};

template

classHand {public:intscore() {int score = 0;for(T card : cards) {

score+=card.value();

}returnscore;

}voidaddCard(T card) {

cards.add(card);

}protected:

vectorcards;

};class BlackJackCard: publicCard {public:

BlackJackCard(intc, Suit s): Card(c,s) {};intvalue() {if (isAce()) return 1;else if (_faceValue >= 11 && _faceValue <= 13) return 10;else return_faceValue;

}intminValue() {if (isAce()) return 1;else returnvalue();

}intmaxValue() {if (isAce()) return 11;else returnvalue();

}boolisAce() {return _faceValue == 1;

}boolisFaceCard() {return _faceValue >= 11 && _faceValue <= 13;

}

};class BlackjackHand: public Hand{public:intscore() {

vector scores =possibleScores();int maxUnder = INT_MIN, minOver =INT_MAX;for(auto a : scores) {if (a > 21 && a

minOver=a;

}else if (a <= 21 && a >maxUnder) {

maxUnder=a;

}

}return maxUnder == INT_MIN ?minOver : maxUnder;

}bool busted() { return score() > 21; };bool is21() { return score() == 21; };bool isBlackJack() {}; //...

private:

vector possibleScores() {}; //...

};