可以访问一个 class 中的播放器结构，但不能访问另一个

Question

I am filling two players' hands with random dominoes and have no issue. When I send the struct to another class, I cannot access the players hands anymore.

using namespace std;
struct player {
    int playerNum;
    vector < pair <int, int>> hand;
};
vector < pair <int, int>> availablePieces;

void Player::createHand(vector < pair <int, int>> &multiVector, player* player) {
    srand(time(NULL)); // rand seed
    int ranNumb;
    //fill players' hand
    for (int i = 0; i < 10; i++) {
        ranNumb = rand() % multiVector.size();
        player[0].hand.push_back(multiVector[ranNumb]);
        multiVector.erase(multiVector.begin() + ranNumb);
        ranNumb = rand() % multiVector.size();
        player[1].hand.push_back(multiVector[ranNumb]);
        multiVector.erase(multiVector.begin() + ranNumb);
    }
}
setAvailablePieces(multiVector);

void Player::createPlayers(vector < pair <int, int>>& multiVector) {
    struct player* domiPlayer = new struct player[2];
    domiPlayer[0].playerNum = 1;
    domiPlayer[1].playerNum = 2;
    createHand(multiVector, domiPlayer);

}
Game gameObj;
gameObj.API(player, availablePieces);

Game Header:

using namespace std;
class Game
{
public:
    void API(struct player* player, vector < pair <int, int>> &availablePieces);
private:
    void playGame(player* player, vector < pair <int, int>>& availablePieces);
};

Game Class:

void Game::playGame(player* player, vector < pair <int, int>>& availablePieces) {
    cout << player[0].hand[0].first << endl;
}
void Game::API(player* player, vector < pair <int, int>> &availablePieces) {
    playGame(player, availablePieces);
}

In the function playGame, I cannot access the individual players hands. I get the error: Expression must be a pointer to a complete object type.

Answer 1

My initial answer was incorrect (apologies). But after looking at this again I think I see your issue (in addition to the leaking of your player objects when createPlayers finishes as @TedLyngmo mentioned).

When you create your players you use struct again. This isn't needed as you've already defined player as a struct. See below, where I've made a more minimal example of your code, initializing players and storing them within the Game class:

#include <stdio.h>

struct player {
    int test = 2;
};

class Game {
    public:
        Game(const int nPlayers);
        void playGame();
    private:
        player *players;
};

Game::Game(const int nPlayers) {
    players = new player[nPlayers];
}

void Game::playGame() {
    printf("%d\n", players[0].test);
}

int main() {
    const int nPlayers = 2;
    Game game(nPlayers);
    game.playGame();
}

This solves the problem of players going out of scope as well as not using struct again when initializing players . I also omitted the Player class as it was not clear where that comes from in the code you posted.