C++ 错误：成员无法访问
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Error: Member is inaccessible
提问by LazySloth13
I have these two classes:
我有这两个类：
class Hand
{
public:
int getTotal();
std::vector<Card>& getCards();
void add(Card& card);
void clear();
private:
std::vector<Card> cards;
};
class Deck : public Hand
{
public:
void rePopulate();
void shuffle();
void deal(Hand& hand);
};
Where the shuffle()function is declared as follows:
当shuffle()函数声明如下：
void Deck::shuffle()
{
std::random_shuffle(cards.begin(), cards.end());
}
However, this returns the following error:
但是，这会返回以下错误：
'Hand::cards' : cannot access private member declared in class 'Hand'
Should I just include a function such asstd::vector<Card>& getCards()or is there another way to avoid the error.
我是否应该只包含一个函数，例如std::vector<Card>& getCards()或者 是否有另一种方法来避免错误。
采纳答案by Ahmed Masud
You can declare cards as protected:
您可以将卡片声明为protected：
class Hand
{
public:
int getTotal();
std::vector<Card>& getCards();
void add(Card& card);
void clear();
protected:
std::vector<Card> cards;
};
class Deck : public Hand
{
public:
void rePopulate();
void shuffle();
void deal(Hand& hand);
};
回答by Nicholas
Since your class Deck inherits from Hand (and it is not a friend class nor is the method Deck::shuffle()), you could simply make cardsprotectedinstead of private. This ensures the encapsulation is in place but the method is accessible by all derivative classes.
由于您的类 Deck 继承自 Hand（并且它不是朋友类，也不是方法Deck::shuffle()），您可以简单地用 makecardsprotected代替private。这确保封装到位，但所有派生类都可以访问该方法。
Just take a look, among other references and tutorials, there:
看看其他参考资料和教程，有：
回答by Nima Soroush
In case of inheritance (your case) the best solution is to make cardsprotected:
在继承（你的情况）的情况下，最好的解决方案是cards保护：
protected:
std::vector<Card> cards;
But in general you can make them friends.
但总的来说，你可以让他们成为朋友。
class Hand
{
friend class Deck;
public:
int getTotal();
std::vector<Card>& getCards();
void add(Card& card);
void clear();
private:
std::vector<Card> cards;
};
