C++传递结构体指针报错求助：扑克游戏代码指针问题

我是C++初学者，确定问题出在对指针的理解上。现在写一款扑克游戏，card是包含suit和value的结构体，玩家手牌和公共牌都用这个结构体填充。尝试把数组引用传给函数，但数组指针的写法肯定有问题，简化后的代码和报错如下：

#include <iostream>
enum suit {hearts, diamonds, spades, clubs};
enum value {two, three, four, five, six, seven, eight, nine, ten, jack, queen, king, ace};

struct card 
{
    value v;
    suit s;
};
static const int num_players = 4;

void get_winner(const card ** hands[num_players][2], const card * mid_cards[5])
{
    for (int i = 0; i < 5; i++) {
        std::cout << "Middle card " << i + 1 << ": " << * mid_cards[i][0] << ", " << * mid_cards[i][1] << "\n";
    }

    for (int i = 0; i < num_players; i++) {
        std::cout << "Player " << i + 1 << "hand: " << * hands[i][0] << ", " << * hands[i][1] << "\n";
    }
}

int main()
{
    card hands[num_players][2];
    card mid_cards[5];
    // fill hands and mid_cards with card structs
    hands[0][0] = card {jack, hearts};
    hands[0][1] = card {nine, spades};
    hands[1][0] = card {ace, clubs};
    hands[1][1] = card {ace, hearts};
    hands[2][0] = card {three, diamonds};
    hands[2][1] = card {seven, spades};
    hands[3][0] = card {eight, diamonds};
    hands[3][1] = card {nine, clubs};
    mid_cards[0] = card {five, clubs};
    mid_cards[1] = card {king, hearts};
    mid_cards[2] = card {queen, spades};
    mid_cards[3] = card {two, clubs};
    mid_cards[4] = card {ace, hearts};
    get_winner(&hands, &mid_cards);
}

报错信息 #

main.cpp:17:51: error: indirection requires pointer operand
      ('const card' invalid)
  ...<< "Middle card " << i + 1 << ": " << * mid_cards[i][0] << ", " << * mid...
                                           ^ ~~~~~~~~~~~~~~~
main.cpp:17:80: error: indirection requires pointer operand
      ('const card' invalid)
  ...i + 1 << ": " << * mid_cards[i][0] << ", " << * mid_cards[i][1] << "\n";
                                                   ^ ~~~~~~~~~~~~~~~
main.cpp:42:2: error: no matching function for call to 'get_winner'
        get_winner(&hands, &mid_cards);
        ^~~~~~~~~~
main.cpp:14:6: note: candidate function not viable: no known conversion from
      'card (*)[4][2]' to 'const card **(*)[2]' for 1st argument
void get_winner(const card ** hands[num_players][2], const card * mid_cards[5])
     ^
3 errors generated.

问题分析与修复 #

你的核心问题是数组传递时的指针类型匹配错误，以及对数组访问方式的误解，一步步修正：

1. 修正函数参数类型
   你声明的hands是二维数组card[num_players][2]，传递给函数时不需要用const card **这种复杂的指针，直接用数组引用更清晰（C++11及以上支持），能明确保留数组的大小信息。同理mid_cards是一维数组，参数不需要写成指针数组：

   void get_winner(const card (&hands)[num_players][2], const card (&mid_cards)[5])
   

2. 修正数组访问与输出逻辑

   • 原代码中mid_cards[i][0]完全错误，mid_cards是一维数组，每个元素是card结构体，不是指针数组，不需要解引用*。
   • 直接输出card结构体对象会报错，因为std::ostream默认不支持结构体输出，需要重载<<运算符。

3. 添加结构体输出重载
   在card结构体定义后添加：

   std::ostream& operator<<(std::ostream& os, const card& c) {
       const char* suit_names[] = {"hearts", "diamonds", "spades", "clubs"};
       const char* value_names[] = {"two", "three", "four", "five", "six", "seven", 
                                    "eight", "nine", "ten", "jack", "queen", "king", "ace"};
       os << value_names[c.v] << " of " << suit_names[c.s];
       return os;
   }
   

4. 修正函数调用
   参数改为数组引用后，直接传数组名即可，不需要取地址：

   get_winner(hands, mid_cards);
   

完整修复后的代码 #

#include <iostream>
enum suit {hearts, diamonds, spades, clubs};
enum value {two, three, four, five, six, seven, eight, nine, ten, jack, queen, king, ace};

struct card 
{
    value v;
    suit s;
};

// 重载<<运算符用于输出card结构体
std::ostream& operator<<(std::ostream& os, const card& c) {
    const char* suit_names[] = {"hearts", "diamonds", "spades", "clubs"};
    const char* value_names[] = {"two", "three", "four", "five", "six", "seven", 
                                 "eight", "nine", "ten", "jack", "queen", "king", "ace"};
    os << value_names[c.v] << " of " << suit_names[c.s];
    return os;
}

static const int num_players = 4;

// 使用数组引用作为参数
void get_winner(const card (&hands)[num_players][2], const card (&mid_cards)[5])
{
    std::cout << "Middle cards:\n";
    for (int i = 0; i < 5; i++) {
        std::cout << "Middle card " << i + 1 << ": " << mid_cards[i] << "\n";
    }

    std::cout << "\nPlayers' hands:\n";
    for (int i = 0; i < num_players; i++) {
        std::cout << "Player " << i + 1 << " hand: " << hands[i][0] << ", " << hands[i][1] << "\n";
    }
}

int main()
{
    card hands[num_players][2];
    card mid_cards[5];
    // fill hands and mid_cards with card structs
    hands[0][0] = card {jack, hearts};
    hands[0][1] = card {nine, spades};
    hands[1][0] = card {ace, clubs};
    hands[1][1] = card {ace, hearts};
    hands[2][0] = card {three, diamonds};
    hands[2][1] = card {seven, spades};
    hands[3][0] = card {eight, diamonds};
    hands[3][1] = card {nine, clubs};
    mid_cards[0] = card {five, clubs};
    mid_cards[1] = card {king, hearts};
    mid_cards[2] = card {queen, spades};
    mid_cards[3] = card {two, clubs};
    mid_cards[4] = card {ace, hearts};
    get_winner(hands, mid_cards);
}

内容的提问来源于stack exchange，提问作者kjdfsjdsa kafsjna