从函数返回向量并更新向量的对象

Question

我有 3 个 Player 对象，它们作为函数中的引用参数传递。 该函数执行以下操作：

1. 创建 3 个对象的 vector，并根据它们的分数（数据成员）对它们进行冒泡排序。
2. 然后它检查第一、第二或第三等级并返回调整大小的vector。

在main 函数中，当我遍历vector 时，我能够打印获胜者和她的奖励，但它似乎并没有更新实际对象。 如何更新对象？

这是我目前所拥有的：

int enterBet(int balance, int maxBet);
vector <Player> chkWinner(Player &a, Player &b, Player &c, int pot);

bool sorting_method(Player &_1, Player &_2) {
    //Bigger numbers go first
    return _1.m_total > _2.m_total;
}

int main()
{
    Player *player1 = new Player;
    Player *player2 = new Player;
    Player *player3 = new Player;
    vector <Player> winnerArr;
    winnerArr.resize(3);
    int pot = 0;
    int betAmount = 0;
    int maxBet = 10;
    player2->m_name = "Kelly";
    player3->m_name = "Martha";
    int x, y, z;

    winnerArr[0] = *player1;
    winnerArr[1] = *player2;
    winnerArr[2] = *player3;

    sort(winnerArr.begin(), winnerArr.end(), sorting_method);
    cout << winnerArr[0].m_total << ", "
        << winnerArr[1].m_total << ", "
        << winnerArr[2].m_total << endl;

    x = winnerArr[0].m_total;
    y = winnerArr[1].m_total;
    z = winnerArr[2].m_total;

    if (x == y && x == z){
        cout << "Divide pot by 3" << endl;
        //totalArr.resize(3);
    }
    else if (x == y && x != z){
        cout << "Divide pot by 2" << endl;
        winnerArr.resize(2);

    }
    else{
        cout << "Pay full Pot" << endl;
        winnerArr.resize(1);
    }

    int payout;

    if (winnerArr.size() == 3){
        payout = ((pot * 5) / 3);
    }
    else if (winnerArr.size() == 2){
        payout = ((pot * 5) / 2);
    }
    else if (winnerArr.size() == 1){
        payout = (pot * 5);

        for (int i = 0; i < winnerArr.size(); i++){
            cout << winnerArr[i].m_name << " wins " << payout << endl;
            winnerArr[i].m_balance += payout;
            cout << winnerArr[i].m_balance << endl;

        }
    }
    cout << player1->m_name << "'s total: " << player1->m_balance << endl;
    cout << player2->m_name << "'s total: " << player2->m_balance << endl;
    cout << player3->m_name << "'s total: " << player3->m_balance << endl;
    break;
}

Answer 1

正如每个人都指出的那样，您不应该创建一个新数组并修改您已有的数组。 STL 帮助您使用排序功能完成您想要的工作。

首先，你需要：

#include <algorithm>

那么你需要一个排序函数：

bool sorting_method(const Player &_1, const Player &_2){
    //Bigger numbers go first
    return _1.m_total > _2.m_total;
}

最后，您使用排序而不是链式循环：

void chkWinner(std::vector <Player> &totalArr){
    sort(totalArr.begin(), totalArr.end(), sorting_method);
    // Add code here, if you need to perform something else. 
    //totalArr is already in the order you need it to.
{

More information about std::sort()

编辑：我修改了代码以创建一个数组，其中包含指向玩家的指针而不是玩家的副本。

bool sorting_method(Player *_1, Player *_2) {
    //Bigger numbers go first
    return _1->m_total > _2->m_total;
}

int main()
{
    Player *player1 = new Player(2, 1);
    Player *player2 = new Player(5 ,2);
    Player *player3 = new Player(3, 3);
    vector <Player *> winnerArr(3);
    int pot = 0;
    int betAmount = 0;
    int maxBet = 10;
    int x, y, z;

    winnerArr[0] = player1;
    winnerArr[1] = player2;
    winnerArr[2] = player3;

    sort(winnerArr.begin(), winnerArr.end(), sorting_method);
    cout << winnerArr[0]->m_name << ", "
        << winnerArr[1]->m_name << ", "
        << winnerArr[2]->m_name << endl;

请注意，由于该更改，您必须修改所有尝试访问数组的代码，包括排序方法。我写的这段代码已经被修改了，所以你只需要修改它的其余部分。我在创建数组时删除了resize函数并添加了（3）参数。我相信它更简单明了。玩得开心：D